we know that
if ABC is an isosceles right triangle
then
side AC=side BC
angle A=angle B=45 degrees
cos B=adjacent side angle B/hypotenuse
adjacent side angle B=BC
hypotenuse=AB------> 18 ft
angle B=45 degrees
cos 45°=(√2)/2
so
cos 45°=BC/AB-------> solve for BC
BC=AB*cos 45-------> BC=18*(√2)/2------> BC=9√2 ft
AC=BC--------> AC=9√2 ft
the answer part 1) is
the exact lengths of the two sides, AC and BC is
AC=9√2 ft
BC=9√2 ft
Part b) Find the Area of triangle ABC
Area=b*h/2-------> AC*BC/2-----> (9√2)*(9√2)/2--------> 81 ft²
the answer part b) is
the area of triangle ABC is equal to 81 ft²
