One of the angles is 15 degrees less than the other, and their sum is 57 degrees, calculate the large angle.

If one of the angles has an unknown number of degrees, then you can designate it with a letter of the Latin alphabet, for example, degrees.

If the second angle is 15 degrees less than the first, then we write down what it is equal to.

a – 15 degrees.

If the sum of the angles is 57 degrees. then we can make an equation, and then find how many degrees are two angles.

a + (a – 15) = 57;

2a – 15 = 57;

2a = 57 + 15;

2a = 72;

a = 72: 2;

a = 36 (gr.) – 1st.

a – 15 = 36 – 15 = 21 (gr.) – 2nd.

Answer: The large angle is 36 degrees.