The question is below?

A square based pyramid is on the top of cuboid having length and breadth equal to 6 cm and height equal to 10 cm. If the TSA of the combined solid object is 336 cm^2 then find the height of the pyramid.

1 Answer
Jun 7, 2018

drawndrawn

Here the base of the pyramid must be 6xx6cm^2 square.

If the height of the pyramid be h cm,then the height of each triangular side of the pyramid will be b=sqrt(h^2+3^2)cm. Base of each triangular face being 6 cm the total surface area of 4 triangular face will be =4*1/2*6*sqrt(h^2+3^2)

=12sqrt(h^2+3^2)cm^2

So total area of other 5surfaces will be =(4*6*10+6^2)=276cm^2

Hence by the problem

12sqrt(h^2+3^2)+276=336

=>12sqrt(h^2+3^2)=60

=>sqrt(h^2+3^2)=5

=>h^2+9=25

=>h=sqrt16 =4 cm