Answer:
28.27
Step-by-step explanation:
Area of a circle A≈ πr2
3.14 x 3^2 ≈ 28.27
Answer:
A: (3,5)
Step-by-step explanation:
Hopefully this helps
Answer:
Length of the tunnel is 51.7 meters
Step-by-step explanation:
We are given that,
The surveyor is located 54 meters from one entrance at an angle of 56°.
The surveyor is located 31 meters from one entrance at an angle of 13°.
Let the length of the tunnel = x meters
So, using the law of cosines, we get,
i.e. 
i.e. 
i.e. 
i.e. x = 51.7 meters
Hence, the length of the tunnel is 51.7 meters
R2(<span>cos2</span>ϕ−<span>sin2</span>ϕ)−2rcosϕ=0<span><span>r2</span>(<span>cos2</span>ϕ−<span>sin2</span>ϕ)−2rcosϕ=0</span>
<span><span><span>r2</span>cos<span>(2ϕ)</span>−2rcosϕ=0</span><span><span>r2</span>cos<span>(2ϕ)</span>−2rcosϕ=<span>0
Now </span></span></span> divide through by <span><span>r≠0</span><span>r≠0</span></span>
and get
<span><span>rcos<span>2ϕ</span>−2cosϕ=0</span><span>rcos<span>2ϕ</span>−2cosϕ=0</span></span>
or
<span><span>r=2<span><span>cosϕ</span><span>cos<span>2ϕ</span></span></span></span><span>r=2<span><span>cosϕ</span><span>cos<span>2<span>ϕ</span></span></span></span></span></span>
