A rectangular tile measures 16 inches by 4 inches. A square tile has the same area as the rectangular tile....
GMAT Geometry & Trigonometry : (Geo_Trig) Questions
A rectangular tile measures \(16\) inches by \(4\) inches. A square tile has the same area as the rectangular tile. What is the side length, in inches, of the square tile?
4
8
10
16
1. TRANSLATE the problem information
- Given information:
- Rectangular tile: 16 inches by 4 inches
- Square tile has same area as rectangular tile
- Find: side length of square tile
- This tells us we need to find areas and set them equal
2. INFER the solution strategy
- Strategy: First find the rectangular area, then use that area to find the square's side length
- We'll need both area formulas: rectangle \(\mathrm{(length \times width)}\) and square \(\mathrm{(side}^2\mathrm{)}\)
3. SIMPLIFY to find the rectangular area
- Area of rectangle = \(\mathrm{16 \times 4 = 64}\) square inches
4. TRANSLATE the equal area condition
- Since areas are equal: Area of square = 64 square inches
- Using square area formula: \(\mathrm{s}^2 \mathrm{= 64}\)
5. SIMPLIFY to find the side length
- Take the square root: \(\mathrm{s = \sqrt{64} = 8}\) inches
- Since length is positive, we take the positive root
Answer: B (8)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Confusing area with perimeter
Students might think "same area" means "same perimeter" and set up \(\mathrm{4s = 16 + 16 + 4 + 4}\), leading to \(\mathrm{s = 10}\).
This may lead them to select Choice C (10)
Second Most Common Error:
Poor SIMPLIFY execution: Calculation errors in basic operations
Students might incorrectly calculate \(\mathrm{16 \times 4 = 32}\) instead of 64, then find \(\mathrm{\sqrt{32} \approx 5.7}\), leading to confusion about which answer to choose, or they might make errors finding \(\mathrm{\sqrt{64}}\).
This leads to confusion and guessing among the available choices
The Bottom Line:
This problem tests whether students can translate a verbal area relationship into mathematical equations and execute basic area calculations accurately. The key insight is recognizing that "same area" creates an equation between different area formulas.
4
8
10
16