Step-by-step explanation:
of course, we have to use Pythagoras.
c² = a² + b²
c is the Hypotenuse = the side opposite of the 90° angle.
and here is the problem : are 9 and 12 the legs. or is one of them the Hypotenuse ?
I don't know from the description.
let's see what we get one way or the other :
assumption : the known sides are the "legs".
c² = 9² + 12² = 81 + 144 = 225
c = 15 ft
that is a nice number. so, it looks like that was the intention.
just to be sure, here also the other options :
9² = 12² + side²
81 = 144 + side² that makes side² negative, so, not valid.
12² = 9² + side²
144 = 81 + side²
63 = side²
side = sqrt(63) this is not a nice round number, so, we go with the first option.
therefore, the 3 sides are
9 ft, 12 ft, 15 ft
perimeter = 9+12+15 = 36 ft
area = baseline×height/2
since this is a right-angled triangle, the "legs" with the enclosed 90° angle serve as baseline and height.
area = 9×12/2 = 9×6 = 54 ft²
