It says, "Sketch the triangle and use the Law of Cosines to find the indicated value. Round your answer to the nearest hundreth."
Find the third side of a triangle with sides of 120cm and 100cm and an included angle of 47 degrees.
The Side-Angle-Side version of the law of cosines is:
= + - 2···
x² = 120² + 100² - 2·(120)·(100)·cos(47°)
x² = 14400 + 10000 - 16367.96064
x² = 8032,039359
x = 89.62164559 cm
Round to nearest hundredth:
x = 89.62cm
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Find the angle opposite the longest side in a triangle with sides of 43ft, 48ft, and 65ft.
The Side-Side-Side version of the law of cosines is:
=
cos(θ) =
cos(θ) =
cos(θ) =
cos(θ) = -0.0174418605
Find the inverse cosine
θ = 90.99939567° round that to 91.00°
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Find the two smaller angles in a triangle with sides of 7in, 7in, and 13in.
You do this one by yourself. It's a Side-Side-Side case and is done exactly
like the previous one. [The triangle is isosceles, that's why I labeled both
smaller angles the same, θ).
Edwin