GED Mathematical Reasoning TestQuantitative Problem Solving with MeasurementEasy
A contractor is installing a new circular window with a radius of 1.5 feet. To ensure proper sealing, a weatherstripping material needs to be applied around the entire edge of the window. If the material is sold in rolls of 10 feet, how many rolls will the contractor need to purchase?
- A1 roll
- B2 rolls
- C4 rolls
- D3 rolls
Show answer & explanationAnswer & explanation
Correct answer: A. 1 roll
To find the length of weatherstripping needed, calculate the circumference of the circular window using the formula 2πr. Then, divide the circumference by the length of a single roll and round up to the nearest whole number.
Why the other options are wrong
- B. This would be an overestimation, possibly from using diameter instead of radius or an incorrect π value.
- C. This is a very large overestimation, suggesting misunderstanding of the concept.
- D. This is a significant overestimation, indicating a major calculation error.
Circumference of a Circle
The distance around the edge of a circle.
- Formula: C = 2πr or C = πd
- Units are linear (e.g., feet, meters)
- Used for measuring perimeters of circular objects
Memory trick: Round the Radius, Get the Circumference