12. The volume of a square room has a door of 2m x 1.5m and two windows, each of 1m x 15m is 900m If the cost of paving tiles including wage at Rs. 7.50/m² is
Rs. 1687.50, find the cost of colouring 4 walls at Rs. 12.50/m?

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.

3 3 6, because in every triangle the longer side is always shorter than the sum of the other two