Answer: 41
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Work Shown:
See the diagram below.
A rectangle is cut along one of the diagonals to form two right triangles. Focus on just one of the triangles.
a = 9 and b = 40 are legs of the right triangle. The hypotenuse is some unknown value c.
Use the Pythagorean theorem to solve for c
a^2 + b^2 = c^2
9^2 + 40^2 = c^2
81 + 1600 = c^2
1681 = c^2
c^2 = 1681
c = sqrt(1681)
c = 41
The other diagonal is also 41 units long because every rectangle has both diagonals equal to one another.
