Answer:
The proportion is 2/7 = 12/42
x = 12
The answer is 12
So as you can see, -3 is the y-intercept. You would make a point on (-3,0) first. Then from the point, you would go up 1 and go right 2 because the slope is a positive 1/2 slope.
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.