1. How To Use SOH, CAH, TOA To
Solve An Unknowns Of A 90°
Triangle.
Kayla Huffman
10-26-10
1st
Trig
Mr. Phares

2. Sin
• If the roof is 18 feet
long, at a 35° angle.
What is the height of
the roof?
• sin(35)/1 = opp/hyp
• sin(35)/1 = x/18
• 18sin(35) = x
• 10.32 ft = x
• The height of the roof
is 10.32 feet.
35°
x
18ft.

3. Cos
• If a street light’s height
is unknown, and the
shadow is 56 feet long
and it is at a 45° angle.
How tall is the street
light?
• cos(45)/1 = adj/hyp
• cos(45)/1 = x/56
• 56cos(45) = x
• 39.60 ft. = x
• The street light is
39.60 feet tall.
56 ft.
45°
x

4. Tan
• If a building is 30 meters
tall, and it’s shadow the
cast is at a 65° angle.
How wide is it’s shadow?
• Tan(65)/1 = opp/adj
• Tan(65)/1 = 30/x
• 30 = xtan(65)
• 30/tan(65) =
xtan(65)/tan(65)
• 14m = x
• The width of the shadow
is 14 meters.
x
30m
65°

5. Summary
• You can use Soh, Cah, Toa to find
multiple things of a right triangle.
• They are used to find unknown
angles and unknown sides of a right
triangle.
• Soh, Cah, Toa is perfect for finding
the length of a shadow or the height
of a building. With the angles, you
can find the angle that the shadow is
cast from.

6. Summary
• You can use Soh, Cah, Toa to find
multiple things of a right triangle.
• They are used to find unknown
angles and unknown sides of a right
triangle.
• Soh, Cah, Toa is perfect for finding
the length of a shadow or the height
of a building. With the angles, you
can find the angle that the shadow is
cast from.