Question

The length of the sides of four triangles are given. Determine which triangle is not a right triangle.a.5 mm, 12 mm, 13 mmb.20 mm, 48 mm, 52 mmc.6 mm, 8 mm, 10 mmd.11 mm, 24 mm, 26 mm

Answer 1

For a right triangle, the sum of the squares of two shorter side should be equal to the square of the third side. The calculations for each choices are shown below. 

a. (5 mm)² + (12 mm)² = 169 mm²    ;    (13 mm)² = 169 mm²   ;     EQUAL
b. (20 mm)² + (48 mm)² = 2704 mm²   ; (52 mm)² = 2704 mm²  ;    EQUAL
c. (6 mm)² + (8 mm)² = 100 mm²       ;    (10 mm)² = 100 mm²   ;     EQUAL
d. (11 mm)² + (24 mm)² = 697 mm² ;  (26 mm)² = 676 mm²  ;  NOT EQUAL

Therefore, the answer is letter D.