# Area of a triangle

#### Mukilab

Triangle ABC
AC=5
BC=8
Angle ACB=75 degrees

Not sure how to do this, can't apply base height formula, nor pythagoras' theorem, nor heron's formula. What do i do?

#### Wilmer

Calculate AB using Law of Cosines. Then call on Mr. Heron.

#### Mukilab

what is the law of cosines?

Is there a law of sines/tans?

#### e^(i*pi)

MHF Hall of Honor
Triangle ABC
AC=5
BC=8
Angle ACB=75 degrees

Not sure how to do this, can't apply base height formula, nor pythagoras' theorem, nor heron's formula. What do i do?
Use the formula for the area of a triangle (which is derived from the base, height formula)

$$\displaystyle A = \frac{1}{2}ab \sin C$$

Where

• a = BC
• b = AC
• C = Angle ABC

This is because by convention:
side a is opposite angle A
side b is opposite angle B
side c is opposite angle C