Question

if a wire is bent into the shape ofa square is 49cm .when the wire is bent into a semi circular shape,find the radius of semi circle

Answer 1

Length of the wire = 49 cm

Define x:

Let the radius be x

Circumference of a semicircle

Circumference of a semicircle = 2r + 1/2(2πr)

Circumference of a semicircle = 2r + πr

Find the radius:

2r + πr = 49

r(2 + π) = 49

r = 49 ÷ (2 + π)

r =9.53 cm

Answer: The radius is 9.53 cm

Answer 2

☺☺☺here is Your answer OK ....⛪⛪


Area of square = 81 cm²

=> Side= 9 cm

=> Perimeter = 9 x 4 = 36 cm

If this is bent into semicircle of radius r, perimeter = πr + 2r

=> r(π+ 2) = 36

You get value of r from here

A little birdie tells me r = 7 cm

Substitute this value in area formula:

Area = ½ x πr²
OK this step you do..