For example, if the measures of two interior angles of a triangle are 60 degrees and 45 degrees, then the measure of the third angle is:
180 degrees - 60 degrees - 45 degrees = 75 degrees
You can also use the Law of Sines to calculate the angles of a triangle. The Law of Sines states that in a triangle, the ratio of the length of a side to the sine of the opposite angle is the same for all sides and angles.
In other words, if you know the lengths of two sides of a triangle and the measure of one angle, you can use the Law of Sines to find the measures of the other angles.
For example, if the lengths of two sides of a triangle are 5 inches and 7 inches, and the measure of one angle is 30 degrees, then the measures of the other two angles can be found by using the Law of Sines:
```
sin(A)/5 = sin(30 degrees)/7
A = 19.47 degrees
```
```
sin(B)/7 = sin(30 degrees)/5
B = 25.53 degrees
```
The third angle can then be found by subtracting the sum of the measures of the other two angles from 180 degrees:
```
C = 180 degrees - 19.47 degrees - 25.53 degrees
C = 135 degrees
```