Answer:
[tex]\huge\boxed{\sf x = 10}[/tex]
Step-by-step explanation:
Hypotenuse = x
Base = 4
Perpendicular = [tex]\sqrt{84}[/tex]
Using Pythagoras Theorem:
[tex]\sf H^2 = P^2 + B^2\\\\ x^2 = (\sqrt{84} )^2 + (4)^2\\\\x^2 = 84 + 16\\\\x^2 = 100\\\\Taking \ sq \ root \ on \ both \ sides\\\\x = 10\\\\\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807
