# 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).

Correct result:

A =  21.7868 °
B =  38.2132 °
C =  120 °

#### Solution:

Try calculation via our triangle calculator.

$C=180-A-B=180-21.7868-38.2132=12{0}^{\circ }$

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Tips to related online calculators
Cosine rule uses trigonometric SAS triangle calculator.
Pythagorean theorem is the base for the right triangle calculator.

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