D) f(n) = 3 + 4(n-1)
3 = 1st term
4 = common difference among the terms
n = term number you are looking for.
To check: 3, 7, 11, 15, ...
f(1) = 3 + 4(1-1) = 3 + 4(0) = 3 + 0 = 3
f(2) = 3 + 4(2-1) = 3 + 4(1) = 3 + 4 = 7
f(3) = 3 + 4(3-1) = 3 + 4(2) = 3 + 8 = 11
f(4) = 3 + 4(4-1) = 3 + 4(3) = 3 + 12 = 15
The answer is C.
Here's why, nPr = n!/(n-r)!. Plug in 7 for n and 3 for r. And you get 7!/(7-3)!.
Thus, 7!/4! = (7*6*5*4*3*2*1)/(4*3*2*1), which simplifies to 7*6*5 = 210
No it’s not a perfect cube
Answer:
262 square feet
Step-by-step explanation:
The lateral surface is the side surfaces, except top and bottom.
There are 3 lateral surfaces.
The 2 sides are triangles with length 20 and height 8.5
And
The back is a rectangle with length 12 and height 8.5
We sum up all the 3 surface areas, that will give us the answer.
Area of triangle is (0.5) * length * height
So,
Area of 1 triangle = 0.5 * 20 * 8.5 = 80
Area of 2 triangles = 80 * 2 = 160
Area of rectangle = length * height
so,
Area of back rectangle = 12 * 8.5 = 102
Total Lateral Surface Area = 160 + 102 = 262 square feet
