Here are a couple of approaches (EP's is WAY better than mine !!! )
https://web2.0calc.com/questions/if-the-area-of-triangle-abc-is-27-what-is-the-value-of-p
Sides: a = 15 b = 3.606 c = 15.62
Area: T = 27
Perimeter: p = 34.226
Semiperimeter: s = 17.113
Angle ∠ A = α = 73.503° = 73°30'12″ = 1.283 rad
Angle ∠ B = β = 13.325° = 13°19'30″ = 0.233 rad
Angle ∠ C = γ = 93.172° = 93°10'18″ = 1.626 rad
Height: ha = 3.6
Height: hb = 14.977
Height: hc = 3.457
Median: ma = 8.5
Median: mb = 15.207
Median: mc = 7.616
If the area of triangle ABC is 27, what is the value of p?
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Solving this geometry problem in several easy steps:
1) AB = sqrt(122 + 102) = 15.62049935
2) CY = 2*27 / AB = 3.456995759
3) ∠ABO ≅ ∠ YCZ = arctan(12 / 10) = 50.19442891º
4) OZ = 12 * tan∠ABO = 14.4
5) CZ = CY / cos∠YCZ = 5.4
6) p = OZ - CZ = 9
Question: If the area of triangle ABC is 27, what is the value of p?
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In my above post, I was using the wrong diagram.
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Answer: A (3, 12) B (12, 0) C (0, p)
1/ AB = arctan(12 / 9) = 15
2/ CY = 2*27 / 15 = 3.6
3/ ∠ABO ≅ ∠YCZ = arctan(12 / 9) = 53.13010235º
4/ OZ = 12 * tan ∠ABO = 16
5/ CZ = CY / cos∠YCZ = 6
6/ p = OZ - CZ = 10
( See above diagram )