Itβs ( 6x - 4 ) + ( 2x + 16 ) = 180 because your only focusing on 3 angles ( < pqr ) since their is no equation for < p yet , you use the 2 equations you already have which is < q & < r
Arectangle has a perimeter of 20 cm. the length, x cm, of one side of this rectangle is uniformly distributed between 1 cm and 7 cm. find the probability that the length of the longer side of the rectangle is more than 6 cm long.