The cross section of a tunnel is in the shape of a semicircle surmounted on the longest side of a rectangle whose shorter side measures 6m. If the perimeter of the cross section is 66m. Find the breadth and height of the tunnel

Hello Johnny, let 2L be the longer side of the rectangle which is the diameter of the semicircle
So circumference of semi circle with radius L is 22/7 * L
Perimeter of the given shape = 22/7 * L + 6 + 2 L + 6
This is given as 66 m
So equating we can find the value of L = 10.5 m
Hence height of the tunnel = 10.5 + 6 = 16.5 m
Breadth of the tunnel = 21 m 
Here is the picture