[Video] Q25: A grain silo is built from two right circular cones and a right circular cylinder with internal measurements represented by the figure above. of the following, which is closest to the volume of the grain silo, in cubic feet?

Explanation for Question 25 From the Math (Calc) Section on the Official Sat Practice Test 3

So now we're looking at number 25, which says that a grain silo, 2 which we see above on this belt from two right circular cones here and 3 here, and then a cylinder with these initial measurements. 4 And then it wants to know which of the following is equal to the, 5 um, to the volume of the grain silo. 6 Right? So what we're going to do is we're going to find the volume 7 of this cone. Um, 8 and we're going to multiply it by two because we have two of those 9 cones and then we're going to find the volume of the cylinder. 10 So let's start with the cylinder. The equation for volume of a cylinder is 11 PI R squared times height. We see that our radius is five. 12 So that's PI times 25 times our height of 10, 13 which is PI times 250. 14 And we can plug that into our calculator. 15 Cause we noticed that our answer choices are not in terms of PI. 16 So if we do PI PI times 17 two 50, we get 785.4, 18 right? So that's the area of our cylinder, 19 which means that a and B can't possibly be correct answers because they're far 20 too small. Um, and then we're looking for the area of our cone, 21 right? Volume of, or not area, sorry, 22 volume of a cone volume of a cone is one third times the same 23 equation for volume of a cylinder. So it's going to be one third times 24 PI or radius is still five. So that's going to be 25 when we 25 have the R square, but our height is five. 26 So now we're just going to multiply all of these out to get the 27 total volume of one cone, right? So ...