Section 5.4: Solving For Missing Sides in a Triangle
August 31, 2015
5­4 Solving for missing sides in a triangle
SOH ­ CAH ­ TOA
We can use our trig ratios to solve for missing sides of a triangle.
Once again, the first place we start is with the angle (given).
1. Find x
2. Find y
14 inches
12 inches
35°
x
y
50°
3. Find Z
22.5 inches
39o
z
17.9 inches
4. Find W
45o
w
Section 5.4: Solving For Missing Sides in a Triangle
5. Find r and p
August 31, 2015
degrees: 2nd, APPS, 1
minutes: 2nd, APPS, 2
seconds: ALPHA, +
r
40 feet
52o15'
p
1. Use trig to solve for any side (class picked r)
2. Solve for other variable by either pythagorean theorem or trig
6. Find c and d
degrees: 2nd, APPS, 1
minutes: 2nd, APPS, 2
seconds: ALPHA, +
57 cm
c
27o 45' 45''
d
1. Use trig to solve for any side (class picked d)
2. Solve for other variable by either pythagorean theorem or trig
Section 5.4: Solving For Missing Sides in a Triangle
August 31, 2015
7. A regular pentagon is inscribed in a circle with diameter 8.34 centimeters. The apothem of a regular polygon is the measure of a line segment from the center of the polygon to the midpoint of one of its sides. Find the apothem (a) of the pentagon.