As we know that the standard equation of circle is 
, where <em>r</em> is the radius of circle and centre at <em>(h,k) </em>
Now , as the circle passes through <em>(2,9)</em> so it must satisfy the above equation after putting the values of <em>h</em> and <em>k</em> respectively
After raising ½ power to both sides , we will get <em>r = +5 , -5</em> , but as radius can never be -<em>ve</em> . So <em>r = +</em><em>5</em><em> </em>
Now , putting values in our standard equation ;
<em>This is the required equation of </em><em>Circle</em>
Refer to the attachment as well !
Since we are already given the formula and all the information, the only thing that we have to do is input all the values and simplify until we get an answer. In addition, we must also note that the radius is 4 (because the diameter is equal to twice the radius, meaning that if the diameter is 8, the radius is 4). Using the formula and information given, we get:
Volume = 3 * (4)² * 12
Which simplifies to:
Volume = 3 * 16 * 12
Volume = 576
Now, we need to know the units. Since this is a 3d shape, and the unit for the lengths of the sides are centimeters, this answer will be in centimeters cubed. That means our answer is 576 centimeters cubed.
When looking for the midpoint of a segment defined by two end points, the average of both coordinates are taken. Averaging the 2 x-coordinates give the new x-coordinate, and the same applies for the y-coordinate. This is shown below:
Midpoint = ( (1 + 4)/2 , (-1 + -6)/2 )
Midpoint = (2.5 , -3.5)
