Question

what is radius and what is diameter​

Answer 1

RADIUS:

straight line from the centre to the circumference of a circle or sphere.

DIAMETER:

straight line that runs from one side of a figure and passes through the center

ADDITIONAL INFO:

SOLVE THE FOLLOWING:

Example 1: The radius of a circle is 15 units. Calculate its diameter

SOLUTION:

Given, radius = 15 units

We know that,

Diameter = 2 × radius

= 2 × 15

Therefore, diameter = 30 units

RADIUS:

Example 1:

Example 1:Find the radius of the circle whose center is O (2, 1), and the point P (5, 5) lies on the circumference.

SOLUTION:

The equation of a circle in the cartesian plane is

given by (x − h)2 + (y − k)2 = r2. Substituting the

value of (x, y) as (5, 5) and (h, k) as (2, 1) we get:

$\\ \\ \\ ( {5 - 2)}^{2} + ( {5 - 1)}^{2} = {r}^{2} \\ \\ {(3)}^{2} + ( {4)}^{2} = {r}^{2} \\ \\ 9 + 16 = {r}^{2} \\ \\ 25 = {r}^{2}$

$\\ \\ r = \sqrt{25} \\ \\ r = 5 \: \\ \\ answer$

Therefore, the radius of the given circle is 5 units