Framing & StructuralQuestion 440 of 700

A common rafter must span a horizontal run of 8 feet and rise a vertical height of 6 feet from the top plate to the ridge. Ignoring overhang, what is the approximate line length of the rafter?

a.12 feet
b.14 feet
c.10 feet
d.11 feet

Explanation

The rafter is the hypotenuse of a right triangle: length equals the square root of (8 squared plus 6 squared) = square root of (64 + 36) = square root of 100 = 10 feet. This is the classic 3-4-5 triangle scaled by two. 12 and 14 feet overstate the diagonal, and 11 feet does not match the exact calculation.

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