Basically, this problem wants you to solve the area of the trapezoid given those dimensions, then multiply this to the unit cost to determine the total cost. The formula for the area of trapezoid is written below:
A = (a+b)h/2, where a and b are the lengths of the two bases
A = (15+9)(10)/2 = 120 cm²
Total Cost = 120 cm² * $0.80/cm² = <em>$96</em>
Check the discriminant (always a good idea).
b^2 - 4ac
b = -19
c = -15
a = 10
(-19)^2 - 4(10)(-15)
361 + 600
961
Yes it can be factored, but if you like, you could use the quadratic formula.
x = [- (-19) +/- sqrt(961)]/(2 * 10)
x = [19 +/- 31 ] / 20
x = (19 + 31/20
x = (50)/20
x = 5/2
x = [19 - 31] / 20
x = [- 12]/20
x = -3/5
Getting the factors is a little tricky.
(x - 5/2)(x + 3/5) = 0
The first factor is found by putting
x - 5/2 in that form and multiplying through by 2
1/2 (2x - 5) The 1/2 comes from multiplying by 2.
The second factor is
1/5 (5x + 3)
So the equation will look like
1/2(2x - 5)1/5(5x + 3) = 0 If you multiply by 2 you get
(2x - 5)1/5(5x + 3) = 0 and now multiply by 5 you get
(2x - 5) (5x + 3)
Check
2x*5x - 25x + 6x - 15
10x^2 - 19x - 15 = 0
So everything works out.
Answer:
Step-by-step explanation:
<u>Area formula for equilateral triangle with side a:</u>
<u>The base area is:</u>
The three lateral surfaces have same sides of 10, 10 and 12.
<u>Find each surface area using heron's formula:</u>
- s = P/2 = (10 + 10 + 12)/2 = 16
- s - a = 16 - 10 = 6
- s - b = 6
- s - c = 16 - 12 = 4
<u>Total surface area is:</u>
Correct choice is C
Answer:
Step-by-step explanation:
Answer:
7/20.
Step-by-step explanation:
Simply convert 35% to a fraction. You get 35/100. Then, you are expected to leave your fraction in its simplest form. Do the simplification, and you will derive <u>7/20</u>.