a roof has a pitch of 3/4 one rafter is 40 feet across and the horizontal slope is 20 feet how tall mustthe rafter be Do i use the y=mx+b formula

some how i have a answer of 12 but dont know how i got it

Question

a roof has a pitch of 3/4  one rafter is 40 feet across and the horizontal slope is 20 feet how tall mustthe rafter be         Do i use the y=mx+b formula

some how i have a answer of 12 but dont know how i got it

anonymous · Answer

Well, a roof pitch is the same as the slope (rise over run). But I don't get the part about a horizontal slope. Is it horizontal or is it a slope? I can picture what part of the roof you are taling about there.

anonymous · Answer

*talking

anonymous · Answer

*can't picture, sorry, getting late

anonymous · Answer

Unless, you just mean the peak is in the middle. 20 feet on one side of the roof.

Assuming that, the roof rises three feet for every four feet of horizontal distance, so if the roof continues to rise for 20 feet of horizontal distance, how many three feet's did it rise?

anonymous · Answer

sorry i posted it wrong the question says the roof must have a pitch of 3/5 and one of the rafters is 40 feet across (meaning the horizantial difference is 20 feet) how tall must the rafter be

anonymous · Answer

You can use the same logic. The roof rises 3 feet for every 5 feet of horizontal distance. So if the roof rises for 20 feet of horizontal distance, how much did it rise?