MAKE DECISIONS USING TRIGONOMETRY
(WORD PROBLEMS)
GIVEN
RIGHT-ANGLED
TRIANGLE
OBLIQUE TRIANGLE
(SSA or AAS)
OBLIQUE TRIANGLE
(SAS or SSS)
Example 1:
USE
 Primary Trig Ratios
SOH CAH TOA
 The SINE Law
b
c
a
=
=
sin A
sin B
sin C
 The COSINE Law
a2 = b2 + c2 – 2bccosA
b2 = a2 + c2 – 2accosB
c2 = a2 + b2 – 2abcosC
While camping, people often keep food out of the reach of
animals by hanging it between two trees. A food bag is tied
between two trees that are 5 m apart by two ropes that form
angles of depression of 57o and 40o respectively. Determine
the length of the longest rope, rounded to 1 decimal place.
Which formula is used? ____________________
Unit 1 Lesson 6
Page 1 of 2
Example 2:
A fireman's ladder is inclined at an angle of 530. If the ladder
is 12.5 m long, determine the height of the fireman above the
ground, rounded to 1 decimal place.
Which formula is used? ____________________
Example 3:
Three lights are located in a park along 3 different paths.
The distance between the first light and the second light is
15 m. The distance between the second light and the third
light is 19 m. The distance between the first light and the third
light is 17 m. Calculate the measure of the smallest angle, to
the nearest degree.
Which formula is used? ____________________
Unit 1 Lesson 6
Page 2 of 2