Page 102 - Math Course 1 (Book 2)

Polygons

Largest Area
A. Find the perimeter and area of the f gure.
Examples

2.3 cm
Terri has 19 feet of tape to make an area in the
classroom where the students can read. Which of
these shapes has a perimeter that will work?

4.6 cm
A = ℓw Area of a rectangle

= (4.6)(2.3) ℓ = 4.6, w = 2.3
= 10.58 Simplify.

The area of the rectangle is
Answer
about 10.6 cm .
2
A square with side length of 5 feet

B. Find the circumference and area of the f gure. B circle with the radius of 3 feet

C right triangle with each leg length of 6 feet

D rectangle with a length of 8 feet and a width of
3 feet
Read the Test Item
You are asked to compare the perimeters or
circumference of four different shapes.
C = 2πr Circumference of a circle
= 2π(4) r = 4 Solve the Test Item

≈ 25.1 Use a calculator. Find each perimeter or circumference.

The circumference of the Square
Answer
circle is about 25.1 inches. P = 4s Perimeter of a square
= 4(5) s = 5
= 20 feet Simplify.
A = πr 2 Area of a circle

= π(4) 2 r = 4 Circle
C = 2πr Circumference of a circle
≈ 50.3 Use a calculator.
= 2π3 r = 3

The area of the circle is = 6π Simplify
Answer ≈ 18.85 feet Use a calculator.
about 50.3 square inches.

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