Which equation can be used to find the unknown length, b, in this triangle?
5 in.
4
in
ooo
42+62 - 52
42-d2 = 52
0 5² +4² = 2²
0 52+ b² = 4²

The first and third options are valid.

Step-by-step explanation:

If two of the three sides of a right triangle are 5 inches and 4 inches, then we have to select the equation from options that can be used to find the unknown length b, in the triangle.

The first equation 4² + b² = 5² can be the possible equation.

The second equation 4² - b² = 5², ⇒ 4² = b² + 5² can not be the equation as 4 being the hypotenuse should be the largest side but 4 < 5.

The third equation 5² + 4² = b² can be the possible equation.

The fourth equation 5² + b² = 4²  is similar to the second equation. So, it is not possible.

Therefore, the first and third options are valid. (Answer)