Recall the definition: Let 0 be an angle in standard position. Its reference angle is the acute angle @ formed by the terminal side of 0 and the horizontal axis. Below, express O' in the same units (degrees or radians) as 0. You can enter arithmetic expressions like 210-180 or 3.5-pi. The reference angle of 100 is The reference angle of 350 is The reference angle of 4 is Hint: Draw the angle. The Figures on page 314 of the textbook may be helpful