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One-,. Two-,. Three-Dimensional Shapes. Duane B. Karlin. CEP 811. June 12, 2011. What is GEOMETRY ?. Geometry is the study of shapes. Geometric figures can have one, two, or three dimensions. What is DIMENSION ?. Dimension is a measure in one direction. What is GEOMETRY ?.
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One-, Two-, Three-Dimensional Shapes Duane B. Karlin CEP 811 June 12, 2011
What is GEOMETRY? Geometry is the study of shapes. Geometric figures can have one, two, or three dimensions. What is DIMENSION? Dimension is a measure in one direction.
What is GEOMETRY? Geometry is the study of shapes. Geometric figures can have one, two, or three dimensions. What is DIMENSION? Dimension is a measure in one direction. Ready to try Question 8 again?
MEASUREMENTS can be in U.S. STANDARD or METRIC. U.S. STANDARD: inches, feet, yards, miles 12 inches = 1 foot 3 feet = 1 yard 1,760 yards = 1 mile U.S. STANDARD conversions are trickier to memorize because they do not have a common converting number. METRIC: meter, decimeter, centimeter, millimeter 1 meter = 10 decimeters = 100 centimeters = 1,000 millimeters METRIC conversions are easier to understand because they are multiples of 10.
READY TO LEARN ABOUT… One-dimensional shapes? Two-dimensional shapes? Three-dimensional shapes? Or are you ready to TEST YOUR KNOWLEDGE?
One-Dimensional Shapes One-dimensional shapes are measured in only one direction. This is defined as the LENGTH. LINES are a one-dimensional shape.
One-Dimensional Shapes One-dimensional shapes are measured in only one direction. This is defined as the LENGTH. LINES are a one-dimensional shape. Ready to try Question 1 again?
Two-Dimensional Shapes Two-dimensional shapes can be measured in two directions. Their measurements are LENGTH (or BASE) and WIDTH (or HEIGHT). The distance around is PERIMETER. The enclosed space is AREA. Want a hint about INTERIOR ANGLES? Click on a shape or capital word to learn more.
A Triangle is a “three-sided” shape. Quadrilateral means “four-sided” shape. An Octagon is an “eight-sided” shape. Ready to try Question 9 again?
Radius CIRCLE Diameter Center Circumference
CENTER CENTER: the middle of a circle. It is the same distance from the center to any point on the circle. Center
DIAMETER Diameter DIAMETER: a line segment that passes through the center of a circle and has its endpoints on opposite sides of the circle.
Radius RADIUS RADIUS: a line segment with one endpoint at the center of a circle and the other endpoint on the circle.
CIRCUMFERENCE CIRCUMFERENCE: the distance around a circle. Circumference
CIRCUMFERENCE, instead of PERIMETER, is used to measure the distance around a CIRCLE. CIRCUMFERENCE = 2πr π = 3.14 r = radius 3 inches C = 2 x 3.14 x 3 C = 6.28 x 3 C = 18.84 CIRCUMFERENCE = 18.84 inches
AREA of a CIRCLE is the INTERIOR space. AREA = πr2 A = 3.14 x 32 3 inches A = 3.14 x 3 x 3 3 inches A = 3.14 x 9 A = 28.26 AREA = 28.26 square inches
TRIANGLE The prefix “TRI-” means 3. 3 interior angles 3 sides INTERIOR means inside. The sum of the 3 interior angles always equal 180°.
AREA of a TRIANGLE = ½ BASE (b) x HEIGHT (h) A = ½b xh A = ½ x 6 x 6 A = 3 x 6 A = 18 square inches HEIGHT (6 inches) BASE This formula works for ALL TRIANGLES. (6 inches)
6 types of TRIANGLES. Equilateral Isosceles Scalene Right Acute Obtuse Click on a shape to learn more, or learn about AREA.
60° All three sides are the same length. All interior angles equal 60°. (60° + 60° + 60° = 180°) 60° 60° EQUILATERAL TRIANGLE
REMEMBER: the sum of the interior angles will always equal 180° in a triangle. Two sides are equal. The angles opposite of the equal sides are also equal. ISOSCELES TRIANGLE
All three sides are different lengths. All interior angles are different, but they still equal 180°. SCALENE TRIANGLE
All three sides are different lengths. All interior angles are different, but they still equal 180°. SCALENE TRIANGLE Ready to try Question 6 again?
One angle, opposite the longest side, measures 90°. It is signified by the ☐ symbol. RIGHT TRIANGLE
All 3 interior angles are less than 90°. Equilateral triangles are an example of an acute triangle, but not all acute triangles are equilateral triangles. ACUTE TRIANGLE
One interior angle in an obtuse triangle is greater than 90°. OBTUSE TRIANGLE
QUADRILATERALS The prefix “QUAD-” means 4, as in a 4-sided figure or shape. Click on a shape to learn more.
PERIMETER = distance around a shape PERIMETER = 3 + 3 + 3 + 3 P = 12 inches 3 inches 3 inches 3 inches 3 inches PERIMETER of any shape is calculated by adding the sides together.
AREA = square units it takes to fill a shape AREA = 3 x 3 A = 9 square inches 1 2 3 1 inch 5 6 1 inch 4 3 inches 1 inch 7 8 9 3 inches AREA of a QUADRILATERAL is calculated by multiplying the Length (or Base) by the Width (or Height).
All 4 sides are equal and parallel. All interior angles equal 90°. REMEMBER: A square is a rectangle, but a rectangle is not a square! SQUARE Parallel means the lines always maintain the same distance apart. Parallel lines will never touch.
REMEMBER: A square is a rectangle, but a rectangle is NOT a square! SQUARE Ready to try Question 7 again?
All interior angles equal 90°. RECTANGLE Opposite sides are equal and parallel.
RHOMBUS, or DIAMOND Interior angles equal 90°. A special type of PARALLOGRAM. All 4 sides are equal and parallel.
Opposite sides are equal and parallel. PARALLELOGRAM Opposite angles are equal.
Has one pair of parallel sides. TRAPEZOID
AREA OF A TRAPEZOID = ½ x (BASE 1 + BASE 2) x HEIGHT 10 inches 5 inches 15 inches Area = ½ x (b1 + b2) xh A = ½ x (15 + 10) x 5 A = ½ x (25) x 5 A = 12.5 x 5 AREA = 62.5 square inches
AREA OF A TRAPEZOID = ½ x (BASE 1 + BASE 2) x HEIGHT 10 inches 5 inches 15 inches Area = ½ x (b1 + b2) xh A = ½ x (15 + 10) x 5 A = ½ x (25) x 5 A = 12.5 x 5 AREA = 62.5 square inches Ready to try Question 2 again?
HINT! Remember, the number of degrees in any geometric shape is 180 x (N – 2), where “N” is equal to the number of sides. So, with a PENTAGON, 5-sided shape, we would write: 180 x (5 – 2) = 180 x 3 = 540, so the number of degrees in a PENTAGON is 540°. A HEXAGON, 6-sided shape, has 180 x (6 – 2) = 180 x 4 = 720°. An OCTAGON, 8-sided shape, has 180 x (8 – 2) = 180 x 6 = 1080°.
HINT! Remember, the number of degrees in any geometric shape is 180 x (N – 2), where “N” is equal to the number of sides. So, with a PENTAGON, 5-sided shape, we would write: 180 x (5 – 2) = 180 x 3 = 540, so the number of degrees in a PENTAGON is 540°. A HEXAGON, 6-sided shape, has 180 x (6 – 2) = 180 x 4 = 720°. An OCTAGON, 8-sided shape, has 180 x (8 – 2) = 180 x 6 = 1080°. Ready to try Question 10 again?
SHAPES WITH MORE THAN 4 SIDES Click on a shape to learn more.
The prefix “PENTA-” means 5. PENTAGON No parallel sides. If each side is equal, then each interior angle equals 108°. Interior angles all equal 540°. All 5 sides can be equal, but they don’t have to be.
The prefix “PENTA-” means 5. PENTAGON No parallel sides. Ready to try Question 5 again?
AREA of a PENTAGON Divide the pentagon into 5 equal triangles. A = ½ x 3 x 5 Divide those triangles in half. A = 1.5 x 5 A = 7.5 But this is only the area for one triangle, so we need to multiply this number by the total number of triangles within the pentagon. BASE = 3 inches HEIGHT = 5 inches A = 7.5 x 10 You now have 10 right angle triangles. AREA = 75 square inches The formula for finding the area of a triangle is A = ½ bxh
The prefix “HEXA-” means 6. HEXAGON Interior angles all equal 720°. If each side is equal, which they do not have to be, then each interior angle equals 120°. 3 pairs of parallel sides. Parallel sides are opposite each other.
The prefix “OCTA-” means 8. OCTAGON Interior angles all equal 1080°. If each side is equal, which they may or may not be, then each interior angle equals 135°. 4 pairs of parallel sides. Parallel sides are opposite each other.
Three-Dimensional Shapes Three-dimensional shapes are measured in three directions: length, width, and height. Three-dimensional shapes also have FACES, VERTICES, and EDGES. Click on a shape or capital word to learn more.
FACES REMEMBER: In a three-dimensional shape, you may not always be able to see all of the faces (sides) of the shape. FACES refers to the sides of a shape. In this example, the CUBE has 6 faces, but we can only see 3.
VERTEX (singular), or VERTICES (plural) A VERTEX is where two or more points meet; a corner. This example of a RECTANGULAR PRISM has 8 VERTICES. Once again, not every VERTEX may be visible in a three-dimensional shape.
VERTEX (singular), or VERTICES (plural) A VERTEX is where two or more points meet; a corner. This example of a RECTANGULAR PRISM has 8 VERTICES. Ready to try Question 4 again?
EDGES The EDGE of a shape is the line where two surfaces meet. This CYLINDER has 2 EDGES.