Question

I will mark brailiest if anyone answers the question right. show your work with working.

Answer 1

remaining cardboard area = 122.5πr²

Explanation:

area of original rectangle = length * width

= 18r * 8r

= 144r²

• area of semi circle:
  `(1)/(2)`πr²

Here we have 3 semi circles with radius 3r:

• area of 3 semi circles: 3(
  `(1)/(2)` * π * (3r)²)

: 3(
`(1)/(2)` * π * 9r²)

: 13.5πr²

• area of one semi circle with radius 4r:

(
`(1)/(2)` * π * (4r)²)

(
`(1)/(2)` * π * 16r²)

8πr²

• So the area of remaining cardboard:

area of rectangle - area of 4 semi circles

144r² - 13.5πr² - 8πr²

122.5πr²