If the area of a circle is A, radius of the circle is r and circumference of it is C, then which one of the true?
A. $$rC = 2A$$
B. $$\frac{C}{A} = \frac{r}{2}$$
C. $$AC = \frac{{{r^2}}}{4}$$
D. $$\frac{A}{r} = C$$
Answer: Option A
Solution (By Examveda Team)
Area of circle = ARadius of circle = r
Circumference of circle = C
πr2 = A . . . . . . (i)
2πr = C . . . . . . (ii)
From equation (i) ÷ equation (ii)
$$\eqalign{ & \frac{{\pi {{\text{r}}^2}}}{{2\pi {\text{r}}}} = \frac{{\text{A}}}{{\text{C}}} \cr & \frac{{\text{r}}}{2} = \frac{{\text{A}}}{{\text{C}}} \cr} $$
rC = 2A
This Question Belongs to Arithmetic Ability >> Mensuration 2D
Join The Discussion