+98 
so:
Cos(x) = 7^2 + 10^2 - 10^2/2(7 * 10)
cos(x) = 49/140
acos(0.35) = x
x= 69.5 degrees.
Let me know if this looks good for explaining my answer!
Thanks
+129845 You kinda' have the right idea, StarStrike
Note...BA = CA = 10 m
The Law of Cosines says that
BC^2 = BA^2 + CA^2 - 2(BA)(CA) cos (x) .....so we have...
7^2 = 10^2 + 10^2 - 2(10)(10) cos (x) simplify
49 = 200 - 200 cos(x) subtract 200 from both sides
[ 49 - 200] = - 200 cos(x) divide both sides by - 200
[ 49 - 200 ] / -200 = cos (x)
To find the measure of x, use the arccos (inverse cosine)...make sure you are in "degree" mode...so we have
arccos [ ( 49 - 200) / -200 ] = x = 40.97°
