G5 Sine and Cosine Rules

Question 1

What is the sine rule of you are finding angles?

Answer 1

sinA / a = sinB / b = sinC / c

sinA is always the angle you want to find.

Question 2

What is the cosine rule if you are finding lengths?

Answer 2

a2 = b2 + c2 - 2bc x cosA

a2 is always side you want to find.

Question 3

What is the cosine rule if you are finding angles?

Answer 3

cosA = (b2 + c2 - a2) / 2bc

cosA is always angle you want to find.

Question 4

How would you find the area of a triangle when you only know 2 sides of the triangle and the angle between them?

Answer 4

Use this formula:

area = 1/2ab x sinC

ab are the two sides you know.

sinC is the angle you know (the angle between them).

Question 5

What is S O H C A H T O A?

Answer 5

Sin theta = Opposite / Hypotenuse

Cos theta = Adjacent / Hypotenuse

Tan theta = Opposite / Adjacent

Question 6

What is the sine rule if you are finding lengths?

Answer 6

a / sinA = b / sinB = c / sinC

a is always the side you want to find.