Fundamentals of Math

Fundamentals of Mathematics

5.3 Perimeter and Area In geometry, the 2-D space inside an enclosed figure is known as the area . While perimeter is the distance around a closed figure (i.e. the length of all the sides). Two polygons may have the same perimeter, but different areas or may have the same area, but different perimeters. To calculate the perimeter of any polygon, add the length of all its sides (whether they are equal or not). The calculation of the area of a polygon depends on which polygon you are working with; in a triangle, the area is equal to 1 2 the base times the height. You can let any side of the triangle be the base, but the height must be perpendicular to the base.

Example 5.3

1 2

1 2

(7 cm)(4 cm)

=

ℎ =

1 2 (28 cm 2 ) = 14 cm 2

=

Practice 5.3

Directions: Calculate the area for each triangle.

1.

2.

3.

Answer Key on Page 122

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