(b) is the answer.
Step-by-step explanation:
By the Pythagorean Theorem,
A² + B² = C²
Where:
A = Length of side 1
B = Length of side 2
C = Hypotenuse
This rule applies to all right-angled triangles.
The length of the hypotenuse of a right-angled triangle is always the largest value.
Therefore, we can test the answers with the equation above.
(a)
8² + 18² = 20²
64 + 324 = 400
388 ≠ 400
The rule of Pythagorean theorem doesn't work on a, so (a) is not a right-angled triangle.
(b)
12² + 35² = 37²
144 + 1225 = 1369
1369 = 1369
The rule of Pythagorean theorem works here, so (b) is a right-angled triangle.
