The Cosine Rule

$A triangle ABC\, with side lengths AB = 20\text{ nm}, BC = 25\text{ nm}, and AC = 35\text{ nm}. The angle at vertex B\, is labeled ABC.$

Three buoys $A$ , $B$ , and $C\,$ form a triangle. The distance $A B = 20$ nautical miles (nm), $25\text{ nm}$ , and $35\text{ nm}$ .

Work out the size of angle $A B C$ .
Give your answer to the nearest degree.

[3]

The Cosine Rule

$A triangle ABC\, with side lengths AB = 20\text{ nm}, BC = 25\text{ nm}, and AC = 35\text{ nm}. The angle at vertex B\, is labeled ABC.$

Three buoys $A$ , $B$ , and $C\,$ form a triangle. The distance $A B = 20$ nautical miles (nm), $25\text{ nm}$ , and $35\text{ nm}$ .

Work out the size of angle $A B C$ .
Give your answer to the nearest degree.

[3]

The Cosine Rule

The Cosine Rule Questions