Answer:
C
Step-by-step explanation:
80 is less than 81, but more than 68.
This is the formula:
Arc length = 2(3.14)(3)(60/360)
18.84(60/360)
18.84 x 0.16 = 3
The length of the arc = 3
Each person eats 7/9 of the pizza.
There are 9 people and 7 pizzas; each person gets an equal amount.
7 pizzas divided by 9 people is 7/9.
Perfect squares follow this pattern:
![(a\pm b)^2 = a^2\pm 2ab+b^2](https://tex.z-dn.net/?f=%20%28a%5Cpm%20b%29%5E2%20%3D%20a%5E2%5Cpm%202ab%2Bb%5E2%20)
So, two terms must be perfect squares of two certain roots. If so, the remaining term must be twice their product. Let's analyse the trinomials one by one:
1) x^2 is the square of x. -64 is not a perfect square. So, the trinomial is not a perfect square.
2) 4x^2 is the square of 2x. 9 is the square of 3. The remaining term, 12x, is indeed twice their product. So, we have
![4x^2 +12x +9 = (2x+3)^2](https://tex.z-dn.net/?f=%204x%5E2%20%2B12x%20%2B9%20%3D%20%282x%2B3%29%5E2%20)
3) x^2 is the square of x. 100 is the square of 10. The remaining term, 20x, is indeed twice their product. So, we have
![x^2 +20x +10 = (x+10)^2](https://tex.z-dn.net/?f=%20x%5E2%20%2B20x%20%2B10%20%3D%20%28x%2B10%29%5E2%20)
4) x^2 is the square of x. 16 is the square of 4. The remaining term, 4x, is not twice their product (it's only the product of 4 and x, so it should be doubled). So, this trinomial is not a perfect square.
#1 is -32
#2 is -11
#3 is -5
#4 is 6