. In triangle DEF, the measure of angle D is 122º. Angle E is acute, and angle F is 19º. What is the measure of angle F in degre
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Answer:
AB ≈ 14.3
Step-by-step explanation:
We're given <em>two sides </em>(BC and CA) and an <em>angle </em>(C)<em> between them</em>; the <em>law of cosines </em>is a good tool for calculating the third side of the triangle here. To remind you, the law of cosines tells us the relationship between the sides of a triangle with side lengths a, b, and c:
Where C is the angle between sides a and b. c is typically the side we're trying to find, so on our triangle, we have
Substituting these values into the law of cosines:
