Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 5 - No. 29)
If two sides of a triangle are 5 and 12, and the included angle is 90 degrees, what is the length of the third side?
7
13
17
169
คำอธิบาย
Pythagorean theorem: 5^2 + 12^2 = c^2; c=13