Answer:
b = [tex]\sqrt{45}[/tex]
Step-by-step explanation:
Using Pythagoras' identity in the right triangle on the left.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
b² + 6² = 9²
b² + 36 = 81 ( subtract 36 from both sides )
b² = 45 ( take the square root of both sides )
b = [tex]\sqrt{45}[/tex]
