Given angles 0.1141 rads and 0.1141 rads, with included side 1392 meters long. How long are the other sides

Question

Help please

Answer 1

This is isosceles triangle with base of 1392 m and two angles on its ends that measure 0.1141 rad.

So, third angle (across the base) will be: Pi - 0.1141-0.1141=3.14-2*0.1141=3.14-0.2282≈2.91

 

Now, use the Law of Cosines:

1392²=x²+x²-2*x*x*cos(2.91)=2x²-2x²*(-0.97)=2x²+1.95x²=3.95x²

So:

3.95x²=1392²   ...square root both sides

1.987x=1392     ...divide by 1.987

x=700.55

x≈700