You can use the equation

to find the lenth of the legs
x = leg 1
x + 14 = leg 2
The ratio is common, so you could write:
a1 * r^4 = a^5 (you do r^4 because there are 4 times you need to multiply by the ratio to get from a1 to a5)
Plug in the values:
3 * r^4 = 48
Divide by 3:
r^4 = 16
Take the fourth root of both sides:
r = 2
The common ratio is 2.
31 out of 50 is
62%Divide 31 over 50:

Multiply 0.62 and 100. This will convert the decimal to a percentage: