Answer:
9. Yes
10. No
11. No
12. Yes
Explanation:
To see if the following lengths make a right triangle, you have to apply the Pythagorean theorem to the triangle.
Which is a² + b² = c²
If the square of the length of the longest side of a triangle is equal to the sum of the squares of the other two sides, then the triangle is a right triangle.
9.
15² + 36² = 39²
225 + 1296 = 1521
1521 = 1521
So this is a right triangle
10.
6² + 8² = 9²
36 + 64 = 81
100 ≠ 81
So this is not a right triangle
11.
6.4² + 12² = 12.2²
40.96 + 144 = 148.84
184.96 ≠ 148.84
So this is not a right triangle
12.
2.1² + 7.2² = 7.5²
4.41 + 51.84 = 56.25
56.25 = 56.25
So this is a right triangle