Q2
ArithmeticGeometry & Mensuration
The area of the circum circle of the equilateral triangle is 154 cm². The length of the longest side of the triangle
- a.$7\sqrt{3}$ cm
- b.7 cm
- c.3·5 cm
- d.28 cm
Answer: (A) $7\sqrt{3}$ cm
$\pi r^2 = 154$ gives $r^2 = 49$, so the circumradius is 7 cm. For an equilateral triangle the side equals $r\sqrt{3}$, so every side (and hence the 'longest') is $7\sqrt{3}$ cm. 7 cm is the radius itself, not the side, and 3·5 cm and 28 cm do not fit the formula.