**A 90-degree turn is one-quarter of turn regardless of direction.** If a person imagines himself standing looking straight ahead and then turning to face the right side or the left side, he has made a 90-degree turn.

A circle contains 360 degrees. If a person imagines himself standing in the middle of a clock and facing the 12 o'clock position and then turning to the right to face the 3 o'clock position or to the left to face the 9 o'clock position, he has made a 90-degree turn, which is one-quarter of a complete circle. If he again faces the 12 o'clock position and turns either to the right or to the left to face the 6 o'clock position, he has made a 180 degree turn, which is half of a complete circle. If he returns to the 12 o'clock position and turns to the right to face the 9 o'clock position or to the left to face the 3 o'clock position, he has turned 270 degrees, which is three-quarters of a complete circle. If he faces the 12 o'clock position and turns all the way to the right or left to return to the 12 o'clock position, he has turned 360 degrees, which means he has made a complete circle.