Mathematics - Properties of Triangle Question with Solution | TestHub

Products cot A cot B=c, cot B cot C=a, cot C cot A=$a^2$. For A+B+C=$\pi$, cot A cot B+cot B cot C+cot C cot A=1, so c+a+$a^2$=1. Existence example a=.4,c=.44 yields positive cot values and angles summing to 180°, so option A is not merely formal.