Easy

Law of Cosines: Problems with Solutions

Problem 1
In a triangle ABC, AC=3, BC=5, AB=6. Find $$\cos(\angle ACB)$$.
In the answer box, write the fraction as a/b. If it is negative, write "-" directly before the fraction.
Problem 2
Given a triangle ABC with AC=12, BC=10 and $$\angle ACB = 60^\circ$$, find the value of AB2 = ?.
Problem 3
Given a triangle ABC with AC=17, BC=14 and $$\angle ACB = 60^\circ$$, find the value of AB2 = ?.
Problem 4
Given a triangle ABC with AC=22, BC=21 and $$\angle ACB = 60^\circ$$, find the value of AB2 = ?.
Problem 5
Given a triangle ABC with AC=8, BC=6 and $$\angle ACB = 60^\circ$$, find the value of AB2 = ?.
Easy

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