It is 77.5. Using a calculator is more useful. ☺
Step-by-step explanation:
eqn of line : y = mx+ c
m = slope or gradient
c = y-intercept.
Lets take (1,6) = (x1,y1) and (2,3) = (x2,y2)

Substitute x = 1 and y = 6 into equation,

Therefore substituting m and c value, equation of line is

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.
Binomial is the correct type of polynomial for this problem