Question

determine the length of the third side of a triangle from the choices provided If the two sides measure 10 and 12

15
30
22
24

Answer 1

Use the triangle inequality: a third side x must satisfy |12 − 10| < x < 12 + 10, i.e. 2 < x < 22. From the choices only 15 lies strictly between 2 and 22, so the third side is 15. (22 would give a degenerate straight line, not a triangle.)