Algebra 3 Unit 11 Variation and Problem Solving Worksheet Name:____________________________________ Date:__________ Period:_____ Write an equation to describe each variation. Use k for the constant of variation. 1. y varies directly as x. 2. a varies inversely as b2 3. y varies jointly as q, r, and t. Find the constant variation for each. Then write the variation equation for each situation. 4. Suppose y varies directly as x, and y = 4 when x = 20. 5. Suppose y varies inversely as x, and y = 20 when x = 9 6. Suppose a varies jointly with x2 and y, and a = 45 when x = 3 and y = 10. 7. Suppose x varies directly as a and inversely as b, and x = -2 when a = 2 and b = 3. Application Problems 8. According to Boyle’s law, the pressure exerted by a gas is inversely proportional to the volume. If a gas exerts a pressure of 1250 pound per square inch when the volume is 2 cubic feet, find the volume when the pressure is 800 pounds per square inch. 9. The intensity I of light varies inversely as the square of the distance d from the light source. When the intensity is 4 when the distance from the light sources is 5 inches, what is the intensity when the distance is doubled?