Well, the area of a trapezoid is A = (

+

) * h * 1/2 so you can use the area of a parallelogram, which is A = l * w, by splitting the trapezoid into 2 triangles and one rectangle. So you'd use A = l * w for the rectangle and A = 1/2bh for the triangles. You'd get the same answer!
2.60 x 12 3/4
2.60 x 12.75 (convert to decimal)
= $33.15, which is not listed.
It is 24in cube value 8 times 3 equals 24
Answer:
Ok, first in our series we can see two numbers in the Sigma, one bellow 0, and other above, 4.
This means that the value of k will go from 0 to 4, then all the numbers in the sum are:
(-1/2)^0 + (-1/2)^1 + (-1/2)^2 + (-1/2)^3 + (-1/2)^4
So we have 5 terms in our series.
b) to see the sign in each term, we must solve the powers, remember that:
(-1)^n is -1 if n is odd, and is equal to 1 if n is even, so we have:
(-1/2)^0 + (-1/2)^1 + (-1/2)^2 + (-1/2)^3 + (-1/2)^4
= 1 -1/2 + 1/4 - 1/8 + 1/16.
So the sign in each term of the series alternates.