`alpha=sin^(-1)(36/85),sinalpha=36/85,tanalpha=36/77`
`beta=cos^(-1)(4/5)=sinbeta=3/5,tanbeta=3/4`
`gamma=tan^(-1)(8/15),tangamma=8/15`
`tan(alpha+beta+gamma)=(sumtanalpha-pitanalpha)/(1-sumtanalphatanbeta)`
`=(36/77+3/9+8/15-36/77*3/4*8/15)/(1-(36/77*3/4+8/15*3/4+8/15*36/77))`
`tan(alpha+beta+gamma)=oo`
`alphaa+beta+gamma=pi/2`
`1=tanalphatanbeta+tanbetatangamma+tanalphatangamma`
`cotalpha+cotbeta+cotgamma=cotalphacotbetacotgamma`.