20.21 multiplied by 999.801 is 20,205.97821, so the correct answer would be A. about 20,000
<span>x-y=11 2x+y=19
x=11+y
2(11+y)+y=19
22+2y+y=19
3y=-3
y=-1
x=11-1=10</span>
Answer:
Last choice. d.
Step-by-step explanation:
We are given the first term and the sixth term.
The first term is 
.
The sixth them is 
.
Let's solve for the common ratio, r.
Divide both sides by -9:
Take the fifth root of both sides:
So the common ratio is 4.
Answer:
Actually it's not polygon. it's a nonagon. With r=8.65mm″, the law of cosines gives us side a:
a=√{b²+c²−2bc×cos40°}
a=√{149.645−149.645cos40°}
Area Nonagon = (9/4)a²cos40°
=9/4[149.645−149.645cos40°]cot20°
=336.70125[1−cos(40°)]cot(20°)
Applying an identity for the cos(40°) does not get us very far…
= 336.70125[1−(cos2(20°)−1)]cot(20°)
= 336.70125[2−cos2(20°)]cot(20°)
= 336.70125[2−(1−sin2(20°))]cot(20°)
= 336.70125[1+sin2(20°)]cos(20°)sin(20°)
= 336.70125[cot(20°)+sin(20°)cos(20°)]mm²
