Question 150621
Find the length of the missing side of the right triangle in which a = 12 and c = 20
Assuming that you are using the conventional lettering for the sides of a right triangle in which the hypotenuse is labeled c, then you can use the Pythagorean theorem to find the length of the missing side, b.
{{{c^2 = a^2+b^2}}} Solve this for b.
{{{b^2 = c^2-a^2}}} Take the square root of both sides.
{{{b = sqrt(c^2-a^2)}}} Substitute a = 12 and c = 20.
{{{b = sqrt(20^2-12^2)}}} Simplify.
{{{b = sqrt(400-144)}}}
{{{b = sqrt(256)}}} 
{{{b = 16}}}