# Angles by cosine law

Calculate the size of the angles of the triangle ABC, if it is given by: a = 3 cm; b = 5 cm; c = 7 cm (use the sine and cosine theorem).

Result

A =  21.787 °
B =  38.213 °
C =  120 °

#### Solution:

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#### To solve this example are needed these knowledge from mathematics:

Cosine rule uses trigonometric SAS triangle calculator. See also our trigonometric triangle calculator. Pythagorean theorem is the base for the right triangle calculator.

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