Question

A triangle has sides of length 7cm and 6cm. calculate length of the third side.
a. 2.42b. 3.61c. 4d. 4.5

Answer 1

We assume the triangle is a right triangle and the side of length 7 cm is the hypotenuse. Then the Pythagorean theorem applies.
  7^2 = 6^2 + (third side)^2
  third side = √(49 - 36) = √13
  third side ≈ 3.61

The appropriate choice is ...
  b. 3.61