Question 498658
You can find the area of any triangle by:
{{{A = (1/2)b*h}}} Where b = the length of the base and h = the height of the triangle.
It doesn't matter which leg you call the base, so we'll say {{{b = 9}}} and {{{h = 40}}}, so...
{{{A = (1/2)(9)(40)}}}
{{{highlight(A = 180)}}} square miles.
To find the perimeter, you'll need to know the length of the hypotenuse of the right triangle. Use the Pythagorean theorem: {{{a^2+b^2 = c^2}}} where: {{{a = 9}}}, {{{b = 40}}}, and {{{c}}} is the length of the hypotenuse.
{{{9^2+40^2 = c^2}}} Evaluate.
{{{81+1600 = c^2}}}
{{{1681 = c^2}}} Take the square root of both sides.
{{{41 = c}}} So the length of the hypotenuse = 41 miles.
Now you can add the three sides to get the perimeter P.
{{{P = 9+40+41}}}={{{90}}}miles.