What is the length of the third side of the window frame below

1.

Step-by-step explanation:

a^2+b^2=c^2

since the hypotenuse is 78 you would square it and the other known number. After squaring both you subtract 6084-5184 and get 900. you would then take the square root and get 30.  

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6