x is even.

y is a multiple of 5.

x + 10x + y = 180.

11x + y = 180.

Since x is even, there is nothing you can multiply 11 by which will get you to a number whose last digit is 5. Therefore, y must be a multiple of 10.

x must equal 10, because there is nothing else you can multiply 11 by that is an even number, that ends with a 0 and does not exceed 180.

110 + y = 180.

y = 70.

The first angle is 10, the second angle is 100, and the third angle is 70.