A full circle inside a rectangle

Question

A circle with a 5 foot radius is place inside a 30x20 ft. rectangle. How many square feet of the rectangle remains after the circle is placed inside the rectangl?

Answer 1

Area of circle = ∏r²= 25 ∏≈78.54 ft²

Area of rectangle = (30)(20) = 600 ft²

 

Area of the rectangle remains after the circle is placed inside the rectangle ≈ 600ft² - 78.54ft² ≈ 521.46ft²