Answer:

Step-by-step explanation:
Use Pythagorean theorem since you have a right triangle
= 
225 = 100 +
so x = 
A.
5 * 2 = 10
8 * 2 = 16
10 cm by 16 cm is the new dimensions. Area = 160 sq cm. Perimeter = 52 cm.
B.
5 * 3 = 15
8 * 3 = 24
15 cm by 24 cm is the new dimensions. Area = 360 sq cm. Perimeter = 78 cm.
C.
The areas for the different sized photos both still maintain a ratio of 5:8 cm.
the blank is 162
since 81 and 81 are both perfect squares the middle term (blank) will be the product of their roots times 2
√81=9
√81 =9
9 x 9 x 2
= 162
Just multiply 4*12 and add 6.
answer =54