3 ft
step-by-step explanation:
since the triangle is right use pythagoras' identity to solve for a
the square on the hypotenuse is equal to the sum of the squares on the other two sides, that is
a² + 8² = ( )²
a² + 64 = 73 ( subtract 64 from both sides )
a² = 9 ( take the square root of both sides )
a = = 3