A lampshade made from a piece of sheet plastic has a radius of the inner circle to be 7cm and that of the outer circle is 28cm.

Question

2 years ago

8

if its arc subtends an angle of 315 degree at the center, what is the area of the plastic used to form the lampshade

1 answer:

NNADVOKAT [17] · Answer 1 · 2023-12-14T20:49:35+03:00

The area of the plastic used to form the lampshade is 2021.25 square centimeters

<h3>How to determine the area of the plastic used to form the lampshade?</h3>

The given parameters in the question are:

Outer radius, R = 28 cm

Inner radius, r = 7 cm

Angle, ∅ = 315

The area of the plastic used to form the lampshade is calculated using the following area of sector formula

A = ∅/360 * π(R² - r²)

Substitute the known values in the above equation

A = 315/360 * 22/7 * (28² - 7²)

Evaluate the exponents

A = 315/360 * 22/7 * (784 - 49)

Evaluate the difference

A = 315/360 * 22/7 * 735

Evaluate the product

A = 2021.25

Hence, the area of the plastic used to form the lampshade is 2021.25 square centimeters