The point (7, 4) lies on a circle centered at the origin. Write the equation of the circle and state the radius.

Given:

The point (7, 4) lies on a circle centered at the origin.

To find:

The equation of the circle and the radius of the circle.

Solution:

Distance formula:

The point (7, 4) lies on a circle centered at the origin. So, the distance between the points (7,4) and (0,0) is equal to the radius of the circle.

The standard form of the circle is

           ...(i)

Where, (h,k) is the center of the circle and r is the radius of the circle.

Putting h=0, k=0 and in (ii), we get

Therefore, the equation of the circle is and its radius is .

i think that you should ask google for the answer to that problem because if we don't know it google does

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this