A right triangle is formed, which you can use the Pythagorean Theorem on.
Pythagorean Theorem is a² + b² = c²
a and b are the legs and c is the hypotenuse {side across from right angle}
a² + b² = c² {Pythagorean Theorem}
a² + 6² = 12² {substituted into the Pythagorean Theorem}
a² + 36 = 144 {squared the 6 and 12}
a² = 108 {subtracted 36 from both sides}
a = √108 {took square root of both sides}
a ≈ 10.39 ft
