In a right-angled triangle PDM, the hypotenuse is DM = 26 cm, RM = √507 cm.Find cos D.

univerkov | September 21, 2021 | education

1). Find DP by the Pythagorean theorem:

DP = √ (DM ^ 2 – PM ^ 2) = √ (26 ^ 2 – (√507) ^ 2) = √ (676 – 507) = √169 = 13 (cm).

2). Find cosD. Since cosine is the ratio of the adjacent leg (DP) to the hypotenuse (DM), then:

cosD = DP / DM = 13/26 = 0.5

Answer: cosD = 0.5

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