What you’ll learn
Surface area of 3D figures.
Key idea
The prism length multiplies each base-side length for lateral area; both end faces must also be included.
Surface area counts both triangular ends and three lateral rectangles; all base lengths are supplied, no distance theorem required.
Worked example
Enter the exact value or ordered values in the format requested below.
Find total surface area of a closed right triangular prism with perpendicular base legs 6,8cm, third base side 10cm and prism length 8cm. Enter a number of square cm.
- Two triangular ends contribute 2×(6×8/2)=48cm².
- Three side rectangles contribute (6+8+10)×8=192cm²; all five faces sum to 240cm².
Answer: 240
Quick Check
Evaluate a worked attempt at surface area of 3d figures, identify the first invalid step, and provide the correction.
For a closed right triangular prism with perpendicular base legs 10,24cm, third base side 26cm and prism length 6cm: Step1 sums the three lateral rectangles to 360cm². Step2 adds only one triangular end, yielding 480cm². Locate the first invalid step and correct surface area.