Answer:
Let width of rectangle be x cm.
3x+x+3x+x=39
8x=39
x=39÷8
=39/8
=4/7/8
3x=39/8×3
=117/8
=14/5/8
Hence, length=14/5/8cm while width=4/7/8cm.
Answer:



Step-by-step explanation:
Given
The attached triangle
Required
Find h, x and y
Let the base of the triangle be 15.
So, the area is:




Let the base of the triangle be 25.
So, the area is:



Substitute 

Solve for h



Considering the smallest triangle

So:


This gives:


Take square roots


Solving for y




To find your answer you would divide 21 by 3 which would be 7, once you've got 7 you would multiply it by 9 which would give you the amount of old houses that there is which would be 63.