Which best approximates the area of triangle ABC

a. 97.05
b. 100.50
c. 116.40
d. 120.6

A=bh/2

Question

Which best approximates the area of triangle ABC

a. 97.05
         b. 100.50
         c. 116.40
         d. 120.6

A=bh/2

anonymous · Answer

attachment

anonymous · Answer

area of trinagle is 1/2 *b*h

anonymous · Answer

using pythagoreans theorem find h, one leg will be 30-x

anonymous · Answer

i dont know if 30 is the base

anonymous · Answer

right thats why you find h in relation to the larger triangle, which will have base 30-x

anonymous · Answer

but first you have to find h, using pythagorean theorem

anonymous · Answer

There is another formula for the area of the triangle which will let you get the answer instantly. It is as follows.

$$Area=(ab \sin c)/2$$
Where a and b are the sides opposite to angle A and angle B. Thus, in your situation...

$$Area=((25)(30)\sin 15)/2$$
And from there its simple math :)

anonymous · Answer

ok i will try that way

anonymous · Answer

i dont think i did it right. i got 5795 :(

anonymous · Answer

That's strange, I get approximately 243.85794 units squared. Do it step by step.

sin 15, times 30, times 25, divided by two.

Area=((25)(30)0.65028784)/2 
Area=(750*0.65028784)/2 
Area=243.85794

anonymous · Answer

ohh... i see now

anonymous · Answer

but i got 97.05 and thats the answer in the answer choice

anonymous · Answer

Oh whoops! I wasn't in degrees mode, so my value of sin 15 is wrong, which throws off the whole answer. But you got the right answer and that's good :) Make sure you remember that formula it'll give you an edge over your classmates :)