Daily Archives: April 3, 2017

Grade 10, Math 10

Math 10 Week 7

Leave a comment

This weeks goal is to teach you how to solve an angle and side lengths in the Trigonometry Unit.

Vocabulary:

SOH: S = \frac{O}{H} or Sine = \frac{Opposite}{Hypotenuse} 

CAH: C = \frac{A}{H} or Cosine = \frac{Adjacent}{Hypotenuse}

TOA: = \frac{O}{A} or Tangent = \frac{Opposite}{Adjacent}

 

i) Question One: What is the Angle of JEP to the nearest degree? (How to find an angle knowing two side lengths)

Step 1: Label the triangle 

*According to the reference angle

  1. Across from the reference angle is called the opposite side (O)
  2. Across from the 90^o angle is the hypotenuse (H)
  3. And the left over side is the adjacent side (A)

 

 

 

 

 

 

 

Step 2: Determine which ratio to use

Use the clues from the triangle. We will be using Cosine because we have the clues from the Adjacent and hypotenuse sides. (CAH)

 

 

 

 

 

 

 

 

 

 

 

 

Step 3: Write the equation

The cos angle is unknown so we will be writing it like :

 

Step 4: Get the variable by itself/Solve

*when moving the COS to the other side of the equation it becomes COS^-1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ii) Question two: What is the side length of AP to the nearest degree. (How to find the side length of a triangle knowing one side length and one angle.)

 

 

 

 

 

 

 

 

 

Step 1: Label the Triangle

*According to the reference angle

 

 

 

 

 

 

 

 

 

 

 

Step 2: Determine the ratio

Use the clues from the triangle. We will be using Tangent because we have the clues from the adjacent and opposite sides. (TOA)

 

Step 3: Write the equation/Solve

*We don’t want the variable on the bottom. Reciprocate the fraction and what you do to one side you do to the other.

 

 

 

 

 

X= 50cm  

 

 

 

 

iii) Question Three: What is the side length of AK to the nearest degree. (How to find the side length knowing one side length and one angle .)

Step 1: Label the Triangle

*According to the reference angle

 

 

 

 

 

 

 

Step 2: Determine the ratio

Use the clues from the triangle. We will be using Sine because we have the clues from the hypotenuse and opposite sides. (SOH)

 

 

 

 

 

 

 

Step 3: Write the equation/Solve

 

 

 

 

*We don’t want the variable on the bottom. Reciprocate the fraction and what you do to one side you do to the other.

 

X= 51 cm