Solving Acute or Obtuse Triangles

Front

What is the Cosine Rule?

Back

c² = a² + b² - 2ab cos(C), where c is the side opposite angle C.

Front

What is the Sine Rule?

Back

(a/sin(A)) = (b/sin(B)) = (c/sin(C)), where a, b, c are the sides opposite angles A, B, C respectively.

Front

When do you use the Cosine Rule?

Back

Use the Cosine Rule when you know two sides and the included angle or all three sides.

Front

When do you use the Sine Rule?

Back

Use the Sine Rule when you know two angles and one side or two sides and a non-included angle.

Front

What is the relationship between the angles and sides in a triangle?

Back

The sum of the angles in a triangle is always 180 degrees.

Front

How do you find the length of a side using the Cosine Rule?

Back

Rearrange the Cosine Rule formula to solve for the unknown side.

Front

How do you find an angle using the Sine Rule?

Back

Rearrange the Sine Rule formula to solve for the unknown angle.

Front

What is the Pythagorean Theorem?

Back

In a right triangle, a² + b² = c², where c is the hypotenuse.

Front

What is an acute triangle?

Back

A triangle where all angles are less than 90 degrees.

Front

What is an obtuse triangle?

Back

A triangle where one angle is greater than 90 degrees.