Answer:
I'm pretty sure It's 2172.20 (I may be wrong It's been a while since I did this)
Step-by-step explanation:
We know that
applying the law of cosines
a² = b²+ c²<span> – 2*b*c*cos(A)
</span>
in this problem
a=?
b=20
c=9
A=90°
so
a² = b²+ c² – 2*b*c*cos(A)
but
cos (A)=0
a² = b²+ c²-----> 20²+9²----> a²=400+81----> a²=481-----> a=√481
a=21.93-----> a=22
the answer is
22
Two lines are parallel if they intersect.
The next step in the series is choice D.
