Because if you did not you would not have a exact answer.
Since the diameter is 6 cm, the radius is 3 cm. Use the area formula to get 113.04 cm squared. Then, you multiply that by the height of the rod, which is 20 cm. The volume of one rod is 2260.8 cm cubed. To find how much steel is needed for 189 rods, multiple the volume of one rod by 189. Your answer should be 427291.2 cm³.
Point-slope form of equation is: 
Step-by-step explanation:
Given points are:
(2,-8) and (1,7)
First of all we have to calculate the slope of the line
so,

Point-slope form is given by:

Putting the value of slope

We can put any one of two given points in the equation to find the final form of point-slope form
So
Putting (1,7) in the equation

Hence, point-slope form of equation is: 
Reducing and simplifying

Keywords: Point-slope form, equation of line
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Answer:
A≅407.34 au (area units)
Step-by-step explanation:
we must find the area generated by equations a., b., and c. To do this we must graph and the areas and determine their points to evaluate
As seen in the graphs (1, 2) we have the area generated by equations a. b. and the limits within which the area should be evaluated are those determined by c.
Finally we find A (view graph 3)