2020 · Q89
ABCD is a quadrilateral such that AD = DC = CA = 20 units, BC = 12 units and ∠ABC = 90°. What is the approximate area of the quadrilateral ABCD?
Elementary MathematicsQuadrilaterals and Polygons
- A269 sq units
- B300 sq units
- C325 sq units
- D349 sq units
Explanation
△ADC is equilateral of side 20: area 100√3 ≈ 173.2. △ABC is right-angled at B with hypotenuse AC = 20 and BC = 12, so AB = 16 and area = 96. Total ≈ 269.2 cm² ≈ 269 cm².