Question

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

Answer 1

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

How to determine the area of the plastic used to form the lampshade?

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

Read more about sector areas at:

https://brainly.com/question/22972014

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