The area of the greatest circle, which can be inscribed in a square whose perimeter is 21 cm, is.

A) \$351\frac{1}{2} \times 1/2 cm^2\$

B) \$350\frac{1}{2} \times 1/2 cm^2\$

C) \$346\frac{1}{2} \times 1/2 cm^2\$

D) \$347\frac{1}{2} \times 1/2 cm^2\$

Three circles of radius 3.5 cm each are placed in such a way that each touches the other two. The area of the portion enclosed by the circles is

A) \$1.975 cm^2\$

B) \$1.967 cm^2\$

C) \$19.68 cm^2\$

D) \$21.22 cm^2\$

The area of two ring between two concentric circles, whose circumference are 88cm and 132cm, is.

A) \$78 cm^2\$

B) \$70 cm^2\$

C) \$715 cm^2\$

D) \$660 cm^2\$

The radius of a circular wheel is 1.75 m. The number of revolutions it will make in travelling 11 km is.

A) \$800\$

B) \$900\$

C) \$1000\$

D) \$1200\$

A can go round a circular path 8 times in 40 minutes. If the diameter of the circle is increased to 10 times the original diameter, the time required by a A to go round the new path once travelling at the same speed as before is.

A) \$25 min \$

B) \$20 min \$

C) \$50 min \$

D) \$100 min \$