In triangle EFK, sides EK = 6cm, FK = 4cm, angle = 60. Find the EF side.

univerkov | February 2, 2021 | education

Since we know the lengths of the two sides of the triangle and the angle between them, by the cosine theorem we determine the length of the side ЕF.

ЕF ^ 2 = KF ^ 2 + EK ^ 2 – 2 * KF * EK * CosEKF = 16 + 36 – 2 * 4 * 6 * Cos60 = 52 – 24 = 28.

EF = 2 * √7 cm.

Answer: The length of the EF side is 2 * √7 cm.

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