A trapezoid has parallel sides with lengths of 18 meters and 26 meters. The height of the trapezoid is 24...
GMAT Geometry & Trigonometry : (Geo_Trig) Questions
A trapezoid has parallel sides with lengths of \(\mathrm{18}\) meters and \(\mathrm{26}\) meters. The height of the trapezoid is \(\mathrm{24}\) meters. What is the area, in square meters, of the trapezoid?
- \(\mathrm{528}\)
- \(\mathrm{792}\)
- \(\mathrm{1,056}\)
- \(\mathrm{1,584}\)
528
792
1,056
1,584
1. TRANSLATE the problem information
- Given information:
- Parallel sides with lengths: 18 meters and 26 meters
- Height: 24 meters
- Need to find: Area in square meters
- What this tells us: We have all the measurements needed for the trapezoid area formula
2. TRANSLATE the geometric formula
- Area formula for trapezoid: \(\mathrm{Area} = \frac{1}{2} \times (\mathrm{sum\,of\,parallel\,sides}) \times \mathrm{height}\)
- Substitute our values: \(\mathrm{Area} = \frac{1}{2} \times (18 + 26) \times 24\)
3. SIMPLIFY through calculation steps
- First, find sum of parallel sides: \(18 + 26 = 44\) meters
- Next, multiply by height: \(44 \times 24 = 1,056\)
- Finally, multiply by 1/2: \(\frac{1}{2} \times 1,056 = 528\)
Answer: A) 528 square meters
Why Students Usually Falter on This Problem
Most Common Error Path:
Missing the 1/2 factor (SIMPLIFY execution error): Students correctly identify the trapezoid formula but forget to include the factor of 1/2 in their calculation.
They calculate: \((18 + 26) \times 24 = 44 \times 24 = 1,056\)
This leads them to select Choice C (1,056) instead of the correct answer.
The Bottom Line:
This problem tests whether students can accurately recall and apply the complete trapezoid area formula. The key challenge is remembering that trapezoid area, like triangle area, includes a factor of 1/2 - it's not just base times height like rectangle area.
528
792
1,056
1,584