The question is as follows:
The three sides of a triangle are 10m, 15m, and 20m. What is the area of the triangle?
(20 - x)^2 - x^2 = 15^2 - 10^2
(20 -x)(20 - x) - x^2 = 125
400 - 40x -2x^2 = 125
-40x - 2x^2 = -275
x - 2x^2 = 6.875
-2x^2 = 6.875x
x^2 = -3.4375x
x = -3.4375
Obviously it's not the right answer, but I have no idea how to get the right one. Answers are greatly appreciated!
i have not used heron's formula before but you could do something else with some simple trig.
1) find either angle using the Cosine Rule
2) then find the area using A = BCsinA/2
where A is the angle you found and B and C are the two sides that make the angle.