Engineers made a mistake on the drawings and the trapezoid window dimensions were incorrect. I am missing the length of a leg.

Question

We adjusted the height of the long base to measure the angle of the roof (18.5 for a 4/12 pitch roof) and now I feel so stupid because I can't figure out the length of the top angle leg.

Short base - 18"

Long Base - 38"

Bottom Leg - 60"

Top Leg - ????

Please help!! I am not smarter than a 5th grader, or an engineer!

Answer 1

I just want to clarify... Is the bottom leg perpendicular to the Bases? So that it looks like this:

|\

|-\

|---\

|----\

|-----\

|------\

|-------\

|--------|

|--------|

|--------|

|--------|

|______|

Such that the left side is 38", the right side is 18", and the bottom is 60"?

If so, we can make the top of the trapezoid into a right triangle and use Pythagorean's Theorem.

The left side extends 20" past the right side, so that's one leg of the triangle. The bottom is 60", so that's the bottom leg of the triangle. That makes sense, because it matches the 4/12 roof pitch.

To find the hypotenuse, we use a²+b² = c²

20² + 60² = c²

4000 = c²

c = 63.25"

I hope my assumptions were correct!