Question

What is m∠C ? Anyone willing to help me (:

Answer 1

50°

Explanation:

Use the cosine law:

`AB^2=CB^2+CA^2-(CB)(CA)\cos(\angle C)`

We have:

`AB=6,\ CB=6.5,\ CA=7.5`

Substitute:

`6^2=6.5^2+7.5^2-2(6.5)(7.5)\cos(\angle C)`

`36=42.25+56.25-97.5\cos(\angle C)`

`36=98.5-97.5\cos(\angle C)` subtract 98.5 from both sides

`-62.5=-97.5\cos(\angle C)` divide both sides by (-97.5)

`\cos(\angle C)\approx0.641\to m\angle C\approx50^o`