In a certain right triangle, the two sides that are perpendicular to each other have lengths h = 4.40 m and b = 8.70 m. What is the length of the third side of the triangle?

the third side is the hypotenuse (c) so use hyp^2 = h^2 + b^2 and solve for hyp.

hyp = square root of (h^2 + b^2).

hyp = sqrt[(4.4m)^2 + (8.7m)^2]

hyp = 9.75m