Answer:
x = 6[tex]\sqrt{5}[/tex]
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
x² + 12² = 18²
x² + 144 = 324 ( subtract 144 from both sides )
x² = 180 ( take the square root of both sides )
x = [tex]\sqrt{180}[/tex]
= [tex]\sqrt{36(5)}[/tex]
= [tex]\sqrt{36}[/tex] × [tex]\sqrt{5}[/tex]
= 6[tex]\sqrt{5}[/tex] ← exact value
