SOLUTION: The two sides of the triangle ABC has sides AB=22cm and AC=8. If the area of the triangle 34.98 cm², what is it's perimeter?

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Question 1129377: The two sides of the triangle ABC has sides AB=22cm and AC=8. If the area of the triangle 34.98 cm², what is it's perimeter?
Found 2 solutions by ikleyn, MathLover1:
Answer by ikleyn(52803)   (Show Source): You can put this solution on YOUR website!
.
Triangle ABC has sides AB=22cm and AC=8. If the area of the triangle 34.98 cm², what is it's perimeter?
~~~~~~~~~~~~~~~~~~~

Use the formula 


   Area =  for the area of a triangle, 


where "a" and "b" are two sides lengths and    is the angle between them.


Using given data, find .


Having  ,  find  = +/-.


    ===---> > > Notice that there is NO NEED to find  : all you need is . < < <---===


Then find the length of the third side using  the cosine law.


Then find the perimeter,

---------------

By the way,  since    may have  (and factually has (!))  TWO values at given  ,  you will have
TWO possible values for the third side,  and,  correspondingly,  TWO values for the possible perimeter.

---------------

Regrading the solution by the tutor  @Mathlover1,  keep in mind that she loss one possible answer and makes
a lot of unnecessary calculations on her way  (like finding   ).


Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!
the triangle has sides:



and

If the area of the triangle and , we have






find -> note that divides triangle in two right triangles and side in two parts and

since we know , ,
use Pythagorean theorem to find


then, ->
now use Pythagorean theorem to find
, and





what is it's perimeter?





or, this way:

Use the formula

for the area of a triangle,

where "a" and "b" are two sides lengths and is the angle between them.

Using given data, find .






°
Having , find .

Then find the length of the third side using the cosine law.





Then find the perimeter,




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