Find the sum of the measures of the interior angles of a 52-gon.

We know that
52-gon means a polygon having 52 sides. 
There is a formula for calculating the sum of interior angles of a polygon : 
(2n-4) x 90° or (n-2) x 180° , where 'n' = number of sides. 

Now, for sum of the interior angles of 52-gon: 
(n-2) x 180° 
=(52-2) x 180° 
=50 x 180° 
=9000°

the answer is
the sum of the measures of the interior angles of a 52-gon is 9000°