What is the area of this triangle? Enter your answer as a decimal in the box. Round only your final answer to the nearest tenth.

Question

asked Oct 12, 2021 167k views

1 Answer

Vicer · Answer 1 · 2021-10-17T03:01:45+0000

Greetings from Brasil...

We need to use the Cosine Law in Any Triangle, so we can use Heron's formula.

AC² = AB² + BC² - 2.AB.BC.COS B

AC² = 11² + 9² - 2.11.9.COS 63

AC ≈ 10,63

Heron's Formula:

Area = √[P.(P - AB).(P - BC).(P - AC)]

where P = (AB + BC + AC)/2

P = (11 + 9 + 10,63)/2 ⇒ P ≈ 15,31

Area = √[15,31.(15,31 - 11).(15,31 - 9).(15,31 - 10,63)]