Yes, it is possible even if it is a decimal.
No.
The relation is proportional when it can be written as
y = kx
As soon as you add a constant, you destroy the proportionality.
let
(hypotenuse ) c = 10 in
(perpendicular) a = 8 in
(base) b =?
By using Pythagoras theorem
c^2= a^2+b^2
(10)^2 = (8)^2 +(b)^2
100 = 64 +(b)^2
100- 64 = (b)^2
36 = (b)^2
√36 = b
6 = b
hence b= 6 in
......................................3 yards?
