Which of the following figures has the longest perimeter ?
A
A square of side 10 cm
B
A rectangular of sides 12 cm and 9 cm
C
A circle of radius 7 cm
D
A rhombus of side 9 cm
Correct Answer: A circle of radius 7 cm
(a) Perimeter = (4 × 10) cm = 40 cm(b) Perimeter = 2(12 + 9) cm = 42 cm
(c) Perimeter = $$\left( {2 \times \frac{{22}}{7} \times 7} \right)$$ cm = 44 cm
(d) Perimeter = (4 × 9) cm = 36 cm