The areas of the squares formed by the side lengths of the triangles are given for each triangle below. Which triangles are right triangles? Select the three correct answers. (Figures are not drawn to scale.)

3 squares form a triangle. The squares have areas 6 inches squared, 10 inches squared, 8 inches squared.

4 squares form a triangle. The squares have areas 9 inches squared, 25 inches squared, 16 inches squared.

5 squares form a triangle. The squares have areas 25 inches squared, 169 inches squared, 144 inches squared.

6 squares form a triangle. The squares have areas 7 inches squared, 25 inches squared, 24 inches squared.

7 squares form a triangle. The squares have areas 64 inches squared, 225 inches squared, 289 inches squared.

8 squares form a triangle. The squares have areas 10 inches squared, 26 inches squared, 24 inches squared.

1 answer

To determine which triangles are right triangles, we can apply the Pythagorean theorem. For a triangle with sides of lengths \(a\), \(b\), and \(c\) (where \(c\) is the longest side), it is a right triangle if \(a^2 + b^2 = c^2\).

We will calculate the side lengths for the triangles using the given areas of the squares, and then check if they satisfy the Pythagorean theorem.

  1. Triangle with areas 6, 10, 8:

    • Side lengths: \( \sqrt{6} \), \( \sqrt{10} \), \( \sqrt{8} \)
    • Check: \[ \sqrt{6}^2 + \sqrt{8}^2 = 6 + 8 = 14 \] \[ \sqrt{10}^2 = 10 \]
    • Since \(14 \neq 10\), this is not a right triangle.
  2. Triangle with areas 9, 25, 16:

    • Side lengths: \( \sqrt{9} \), \( \sqrt{25} \), \( \sqrt{16} \)
    • Check: \[ 3^2 + 4^2 = 9 + 16 = 25 \] \[ 5^2 = 25 \]
    • Since \(25 = 25\), this is a right triangle.
  3. Triangle with areas 25, 169, 144:

    • Side lengths: \( \sqrt{25} \), \( \sqrt{169} \), \( \sqrt{144} \)
    • Check: \[ 5^2 + 12^2 = 25 + 144 = 169 \] \[ 13^2 = 169 \]
    • Since \(169 = 169\), this is a right triangle.
  4. Triangle with areas 7, 25, 24:

    • Side lengths: \( \sqrt{7} \), \( \sqrt{25} \), \( \sqrt{24} \)
    • Check: \[ \sqrt{7}^2 + \sqrt{24}^2 = 7 + 24 = 31 \] \[ \sqrt{25}^2 = 25 \]
    • Since \(31 \neq 25\), this is not a right triangle.
  5. Triangle with areas 64, 225, 289:

    • Side lengths: \( \sqrt{64} \), \( \sqrt{225} \), \( \sqrt{289} \)
    • Check: \[ 8^2 + 15^2 = 64 + 225 = 289 \] \[ 17^2 = 289 \]
    • Since \(289 = 289\), this is a right triangle.
  6. Triangle with areas 10, 26, 24:

    • Side lengths: \( \sqrt{10} \), \( \sqrt{26} \), \( \sqrt{24} \)
    • Check: \[ \sqrt{10}^2 + \sqrt{24}^2 = 10 + 24 = 34 \] \[ \sqrt{26}^2 = 26 \]
    • Since \(34 \neq 26\), this is not a right triangle.

Thus, the triangles that are right triangles are:

  • The triangle with areas 9, 25, and 16.
  • The triangle with areas 25, 169, and 144.
  • The triangle with areas 64, 225, and 289.