Review Triangle Key Terms

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1. Review Triangle Key Terms

• A right triangle is any triangle with a right
  angle
• The longest and diagonal side is the hypotenuse
• The other two sides are the opposite side and
  adjacent side (means next to)
• The labels depend on the reference angle

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1. Identifying Sides of Right Triangle for a
Reference Angle
Ex 1 Reference Angle A Identify the Sides (I
DO)
Reference Angle A Hypotenuse Adjacent
Side Opposite Side
AB
Hypotenuse
AC
Opposite
BC
Adjacent
Ex 2 Reference Angle B Identify the Sides (WE
DO)
Reference Angle B Hypotenuse Adjacent
Side Opposite Side
AB
Hypotenuse
AC
Adjacent
BC
Opposite
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2. Finding the Value of Trigonometric Ratios

• There are three main Trigonometric Ratios
• SINE of an ANGLE __OPPOSITE__
• HYPOTENUSE
• COSINE of an ANGLE ADJACENT__
• HYPOTENUSE
• TANGENT of an ANGLE __OPPOSITE__
• ADJACENT
• Remember, SOH CAH TOA

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Ex 3 Find the Value of Sin A (I DO)
2. Finding the Value of Trigonometric Ratios
Reference Angle A Opposite4 Hypotenuse5 Sin
A Opp 4 0.80 Hyp 5 Sin A 0.80
Hyp.
5
Opp
4
3
FIRST, LABEL ALL SIDES! SOH CAH TOA
Adj
Ex 4 Find the Value of Cos A (WE DO)
Reference Angle A Adjacent 3 Hypotenuse5 Cos
A Adj 3 0.60 Hyp 5 Cos A 0.60
Hyp.
5
4
Opp
3
Adj
5
Ex 3 Find the Value of Cos B (WE DO)
2. Finding the Value of Trigonometric Ratios
Reference Angle B Opposite4 Hypotenuse5 Cos
B Adj 4 0.80 Hyp 5 Cos B 0.80
Hyp.
5
Adj
4
3
FIRST, LABEL ALL SIDES! SOH CAH TOA
Opp
Ex 4 Find the Value of Tan B (WE DO)
Reference Angle B Opposite3 Adjacent4 Tan B
Opp 3 0.75 Adj 4 Tan B 0.75
Hyp.
5
Adj
4
3
Opp