Question

The rectangle shown is rotated about line k. What is the approximate base area of the resulting figure? Area of a circle: A = πr2

A. 31 sq. in.
B. 50 sq. in.
C. 79 sq. in.
D. 314 sq. in.

Answer 1

C

Explanation:

Answer 2

Answer:- C is the correct answer. The approximate base area of the resulting figure is 79 Sq.in.

Explanation:-

Given :- A rectangle which is rotated about a line k .

According to the picture the line k dividing the length of the rectangle into two equal halves of 5 inches.

If the rectangle is rotated about line k , the n it will form a cylinder which is the resulting figure with height is same the breadth of rectangle i.e.4 inches and has base of circle with radius is same as half of length i.e. 5 inches.

Now,the base area of the resulting figure (circle)=
`\pi\ r^2=3.14*5^2=3.14*25=78.5\ sq.\ in.\approx79\ sq.\ in.`

Therefore, The approximate base area of the resulting figure is 79 Sq.in.