2022 · Q71
An equilateral triangular sheet is formed by joining 9 equilateral triangular sheets each of area 9√3 cm². What is the height of the bigger triangular sheet?
Elementary MathematicsGeometry: Lines, Angles and Triangles
- A9√3 cm
- B18 cm
- C18√3 cm
- D27 cm
Explanation
The big triangle's area is 9x9√3 = 81√3 = (√3/4)a², so a = 18 cm and its height is (√3/2)x18 = 9√3 cm. Hence the keyed option is A.