Answer:
Perimeter A = 122.5
Explanation:
Set up the following proportion
The Perimeter of B = 12 + 9 + 9 + 5
The Perimeter of B = 35
7/2 = x/PerimeterB
7/2 = x / 35 Cross multiply
7*35 = 2x Combine the left side
245 = 2x Divide by 2
245/2 = 2x/2 Do the division
122.5 = x
The Perimeter of A = 122.5
Problem 3
If you compare the sides opposite the angle marked with a single arc, you will get the scale factor.
If these triangles are similar, and one of the sides opposite their markings will give you the scale factor
18/7.2 = x/1 where x is the scale factor going from the larger to the smaller triangle.
2.5 = x
So if you multiply the smaller triangle's sides by 2.5 you get the larger triangle.