In a triangle ABC, AB+BC=7.1 cm, BC+CA=12.1 cm and CA+AB=7.2 cm. What is the area of the triangle?

  1. A. 3 square cm
  2. B. 32 square cm
  3. C. 33 square cm
  4. D. 3.3 square cm

Correct Answer: D. 3.3 square cm

Explanation

Adding the three equations gives 2(AB+BC+CA) = 26.4 \implies AB+BC+CA = 13.2. Thus, AC=6.1, AB=1.1, and BC=6.0. Since 1.1^2 + 6.0^2 = 37.21 = 6.1^2, it is a right triangle. Area = 0.5 \times 1.1 \times 6 = 3.3 sq cm.

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