we actually already found angles B and C for the last problem I think we said 30 and 32 so we would be able to guess that angle A is about 118° but.. let's do the math... and see
angle A = arcCos[ b^2 + c^2 - a^2 / 2*b* c ]
A = arcCos[ 289 +324 - 900 / 2*17*18]
A = arcCos[ -287 / 612 ]
A = arcCos[ -0.468954 ]
A = 117.9664 °
ohh and we're off by 0.0336 phooy :P soo far off... :P
rounding to nearest 10th
A = 118.0 ° ( ohh right on the money :P) yay, I feel better. :P
