Answer:
The ratio of a to b is 3:5, which means that the value of a is 3/8 of the value of b. This means that if the difference between the angles a and b is 36°, then the size of angle a is 3/8 * 36° = 9°.
To find the size of angle C, we need to add the size of angle a to the size of angle b. Since the size of angle a is 9° and the difference between the sizes of angles a and b is 36°, the size of angle b is 36° + 9° = 45°.
The size of angle C is the sum of the sizes of angles a and b, so the size of angle C is 9° + 45° = 54°. Therefore, the size of angle C is 54°.