Inverse Proportion
Direct and Inverse Proportion · Class VIII
When x y = k, slide k and see y fall as x grows.
- y at sample6
- Product x*y24
- y = k / x
Formulas in this lab
- y at sample
- Product x*y
Frequently asked questions
▶What is inverse proportion?
Two quantities are in inverse proportion if x*y = k, meaning when x doubles, y is halved. The product stays constant. For k = 24, if x = 4 then y = 6, and if x = 8 then y = 3.
▶How do I use the inverse proportion lab?
Slide k (1 to 100) and sample x. The lab shows y = k/x and confirms x * y is always k. Try k = 60 and x = 5 to see y = 12, with product 60.
▶Where is inverse proportion seen in Indian life?
Workers and days: if 4 painters paint a hall in 12 days, then 6 painters can finish it in 4 * 12 / 6 = 8 days. Here k = 48 (total man-days). The lab helps plan such tasks: more workers, fewer days.
▶Direct vs inverse: ratio vs product?
Direct proportion holds the ratio y/x constant; inverse proportion holds the product x*y constant. So in direct, doubling x doubles y; in inverse, doubling x halves y. The two labs side by side make this contrast obvious.