Answer:
V = 140 pi ft^3
Step-by-step explanation:
The volume of a cone is given by
V = 1/3 Bh where B is the area of the base
V = 1/3 (35 pi) * 12
V = 4*35 pi
V = 140 pi ft^3
We cannot approximate pi if we want the exact answer
To find the point of intersection, we want to set the two equations equal to each other to find where they meet. The problem is, we have two variables, which means we can't just set them equal to each other as is. We need to manipulate the equations so that we can remove one of the variables at a time to solve for the other one.
First, let's move y to one side so we can solve for x.
2x-3y=9
2x-9=3y
y=(2x-9)/3
5x+4y=11
4y=11-5x
y=(11-5x)/4
Now that they both equal the same thing (y), we can set them equal to each other and solve for x. This will give us the x value for the point of intersection of the lines.
(11-5x)/4=(2x-9)/3
3(11-5x)=4(2x-9)
33-15x=8x-36
33+36=8x+15x
69=23x
x=69/23
x=3
Now, we can do the opposite, and solve for x to find the y coordinate.
2x-3y=9
2x=3y+9
x=(3y+9)/2
5x+4y=11
5x=11-4y
x=(11-4y)/5
(3y+9)/2=(11-4y)/5
5(3y+9)=2(11-4y)
15y+45=22-8y
15y+8y=22-45
23y= -23
y= -1
The coordinates for the point of intersection of the two lines is (3, -1).
Because ABCD is an isosceles trapezoid, the angles A and D are congruent.
BA and CD are congruent (given) and AD is congruent to itself (reflexive property).
Then triangles BAD and CDA form a pair of SAS triangles, so they are congruent.
BD and CA are corresponding parts in those triangles, so they are congruent (CPCTC).
