Answer:
The measures of the angles at its corners are 
Step-by-step explanation:
see the attached figure to better understand the problem
step 1
Find the measure of angle A
Applying the law of cosines
![cos(A)= [215^{2}+125^{2}-185^{2}]/(2(215)(125))](https://tex.z-dn.net/?f=cos%28A%29%3D%20%5B215%5E%7B2%7D%2B125%5E%7B2%7D-185%5E%7B2%7D%5D%2F%282%28215%29%28125%29%29)
step 2
Find the measure of angle B
Applying the law of cosines
![cos(B)= [215^{2}+185^{2}-125^{2}]/(2(215)(185))](https://tex.z-dn.net/?f=cos%28B%29%3D%20%5B215%5E%7B2%7D%2B185%5E%7B2%7D-125%5E%7B2%7D%5D%2F%282%28215%29%28185%29%29)
step 3
Find the measure of angle C
Applying the law of cosines
![cos(C)= [125^{2}+185^{2}-215^{2}]/(2(125)(185))](https://tex.z-dn.net/?f=cos%28C%29%3D%20%5B125%5E%7B2%7D%2B185%5E%7B2%7D-215%5E%7B2%7D%5D%2F%282%28125%29%28185%29%29)
<h2><em>we can write (3x^2-5y^2) as (3x-5y)^2</em></h2><h2><em>(
3
x
−
5
y
)
2 as (
3
x−
5
y
)
(
3
x−
5
y
)</em></h2><h2><em>3
x
(
3
x
−
5
y
)
−
5
y
(
3x
−5
y
)</em></h2><h2><em>3
x
(
3
x
−
5
y
)
−
5
y
(3
x
−
5
y
)</em></h2><h2><em>3
x
(
3
x
)
+
3
x
(
−
5y
)
−
5
y
(
3
x
)
−
5
y(
-5
y
)</em></h2><h2><em>9
x
2
−
15
x
y
−
15y
x
+
25
y
2
</em></h2><h2><em> Subtract 15
y
x from −
15
x
y
.</em></h2><h2><em>9
x
2
−
30
xy
+
25
y
2</em></h2><h2><em> HOPE IT HELPS(◕‿◕✿) </em></h2><h2><em> SMILE!! </em></h2>
x=11
the angles are congruent so 6x-10=56
6x=66
x=11
