Geometry and TrigonometryMediumArea of a square after one side is shortened
Geometry and Trigonometry practice question
A square has sides of length 10. One pair of opposite sides is shortened to 7.5 while the other pair stays at 10, making a rectangle. By what percent is the area reduced?
Answer: 25
Square area: 100. Rectangle: 10 × 7.5 = 75. The reduction is 25 out of 100, which is 25%.
Common wrong answers
- If you answered 50
- 50 overstates it: shortening one pair of sides by a quarter cuts the area by a quarter, from 100 to 75.
- If you answered 75
- 75 is the NEW area, not the percent reduction.
- If you answered 2.5
- 2.5 is the reduction in one side's length, not in area.
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