I got the answer to be 42.
SA=4pir^2
78.54km^2=SA
78.54=4pir^2
divide both sides by 4
19.635=pir^2
aprox pi=3.14 so divide both sides by 3.14
6.25318=r^2
sqrt both sides
2.50063=r
round
radius=2.5km
this question is flawed in that it gives the wrong units
answer is the option with 2.5 in it
2nd one
The answer would be C.
Sin2 cot2=sin2*cos2/sin2=cos2
Which is not equal to the others.
Hope this helps:)
Answer:
=10
Step-by-step explanation:
1: Add the numbers
2: Factor the numbers
3: Apply radical rule
Answer: =10
<u><em>Hope this helps.</em></u>