Triangles with height 
and base 
, with 
have area 
.
Such cross sections with the base of the triangle in the disk 
(a disk with radius 5) have base with length
i.e. the vertical (in the 
plane) distance between the top and bottom curves describing the circle 
.
So when 
, the cross section at that point has base
so that the area of the cross section would be 6^2/2 = 18.
In case it's relevant, the entire solid would have volume given by the integral
Answer:
7
Step-by-step explanation:
Answer:
x = 9
Step-by-step explanation:
2 sides are 4 less than x, that is x - 4
The perimeter is the sum of all 3 sides, thus
x + x - 4 + x - 4 = 19, that is
3x - 8 = 19 ( add 8 to both sides )
3x = 27 ( divide both sides by 3 )
x = 9
You would do 129/3 so he drove 43 miles per hour
