Which of the following are the sides of a right-angled triangle?

Correct option is C

Given:
To determine which of the given sets of sides form a right-angled triangle, we will use the Pythagorean theorem:
For a set of sides to form a right-angled triangle, the square of the longest side (hypotenuse) should be equal to the sum of the squares of the other two sides.
(a) 6 cm, 7 cm, 10 cm
​$$10^2=100 \\\ \\6^2+ 7^2=36+49=85$$​​
85 ≠100 this does not follow the Pythagorean theorem.
(b) 5 cm, 11 cm, 13 cm
​$$13^2=169 \\\ \\5^2+ 11^2=25+121=146$$​​
146 ≠169 this does not follow the Pythagorean theorem
(c) 12 cm, 16 cm, 20 cm
​$$20^2=400 \\\ \\12^2+ 16^2=144+256=400$$​​
400 =400 this follows the Pythagorean theorem
(d) 16 cm, 31 cm, 34 cm
​$$34^2=1156 \\\ \\16^2+ 31^2=256+961=1217$$​​
1156 ≠1217 this follows the Pythagorean theorem
Hence sides (c) 12 cm, 16 cm, 20 cm are the sides of right-angled triangle.