Triangles

[vampirewitchreine]

I want to check my work for the area of the triangle because it seems that it's odd to have the same answer as the perimeter.

(Black was provided by my textbook, red are my answers)

P= 25.2
A= 25.2



The third side I got by Pythagorean theorem.
\(\displaystyle a^2+b^2=c^2\)
\(\displaystyle 5.6^2+9^2=c^2\)
\(\displaystyle 31.36+81=c^2\)
\(\displaystyle \sqrt {112.36}= \sqrt{c^2}\)
\(\displaystyle 10.6=c\)


So now I'm able to check the perimeter (5.6+9+10.6=25.2)
Or I could have shortened it because the perimeter was already provided to be: 25.2-5.6-9=10.6

Now the area of a triangle is: 1/2bh

So then I have:
A=1/2(9)(5.6)
A=4.5(5.6)
A=25.2

 

[vogler]

Your work looks good. You found the third side in two different ways, and both are correct, and you got the right answer both times.