What this skill covers
This skill covers everyday geometry: computing the area or perimeter of a basic shape, applying the Pythagorean theorem to a right triangle, and understanding measurement relationships between similar figures.
Drawing a quick sketch of the shape described — even a rough one — catches setup mistakes (like using the wrong pair of dimensions) before you calculate.
Worked examples
Example 1
A triangle has a base of 10 units and a height of 6 units. What is its area?
A. 30
B. 60
C. 16
D. 34
Why: Area = ½ × base × height = ½ × 10 × 6 = 30 — forgetting the ½ factor is the most common way to get 60 instead.
Example 2
A right triangle has legs of 9 and 12. What is the length of the hypotenuse?
A. 15
B. 21
C. 13
D. 18
Why: 9² + 12² = 81 + 144 = 225, and √225 = 15 — a scaled-up version of the 3-4-5 right triangle.
How to practice this on TSI Practice Prep
Open TSIA2 Practice to answer original TSIA2 questions on tSIA2 Geometric and Spatial Reasoning, get an explanation for every choice, and see this skill tracked separately in your progress and mistake review.
Practice score estimates are learning indicators, not official scores or admission guarantees.
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