Area of Regular Polygons Using Trig.

Labelling

Label the parts of the octagon.

Drag labels to their correct position on the image

side

interior angle

central angle

apothem

radius

center

Multiple Choice

What is the formula for the area of a regular polygon?

• A = 1/2(Perimeter)(Apothem)

• A = 1/2(Base)(Height)

• A = (Side)^2

• A = 1/2 (Perimeter)(Height)

Math Response

Use the tangent ratio to solve for unknown sides in a right triangle.

Type answer here

Correct Answer: 39.81

Deg^°

Rad

Math Response

Calculate the area of a regular pentagon given a side length of 14 inches.

Type answer here

Correct Answer: 337.05

Deg^°

Rad

Math Response

Find the area of the decagon (10 sides) given an apothem of 7.5 in.

Type answer here

Correct Answer: 183

Deg^°

Rad

Multiple Choice

What is the central angle of a regular nonagon?

• 40°

• 20°

• 60°

• 30°

Math Response

Calculate the area of the regular pentagon.

Type answer here

Correct Answer: 116.31

Deg^°

Rad

Open Ended

When do you use the trigonometric ratios to solve for the area of regular polygons?

Open Ended

Explain how to calculate the area of a regular polygon using trigonometric ratios.