Answer: 6.
- A 6
- B 8
- C 12
- D 10
Correct answer: A. 6
Explanation: Trig area formula: Δ=(1/2)ab sinC. Given a=3, b=4, C=90°: sin90°=1. Area=(1/2)(3)(4)(1)=6. The right angle simplifies sinC to 1, so area is simply half the product of the two enclosing sides.
Unit circle with standard angles 0, 30, 45, 60, 90 degrees; at 45 degrees the point is (cos45, sin45) = (1/sqrt2, 1/sqrt2).
Concept context
Ratios, identities, and applications in triangles