Trigonometry
Pythagoras’ Theorem
◺ a²+ b²= c²
. C² is always referring to the ‘hypotenuse of the triangle’.
. a²and b² refer to the other sides.
. The hypotenuse is the longest side and opposite the right
angle.
* Can only be used when two sides are known and on
right-angle triangles.
Example: Find the hypotenuse where the other two sides
equal 3cm and 4cm.
3𝑐𝑚² + 4𝑐𝑚² = 𝐶²
9𝑐𝑚 + 16𝑐𝑚 = 𝐶²
25 = 𝐶² - We want to know C, not C²
5 = 𝐶 - The answer is not right if the hypotenuse is
smaller than one of the sides
, Labeling a Triangle
Hypotenuse - The longest side and opposite the right angle
Opposite - The side opposite the given angle
Adjacent - The side next to the given angle
Sin, Cos, Tan
- Sine SOH
𝑜𝑝𝑝
𝑆𝑖𝑛 = ℎ𝑦𝑝
- Cosine CAH
𝑎𝑑𝑗
𝐶𝑜𝑠 = ℎ𝑦𝑝
- Tangent TOA
𝑜𝑝𝑝
𝑇𝑎𝑛 = 𝑎𝑑𝑗
SOHCAHTOA - To help remember the trigonometric ratios
Pythagoras’ Theorem
◺ a²+ b²= c²
. C² is always referring to the ‘hypotenuse of the triangle’.
. a²and b² refer to the other sides.
. The hypotenuse is the longest side and opposite the right
angle.
* Can only be used when two sides are known and on
right-angle triangles.
Example: Find the hypotenuse where the other two sides
equal 3cm and 4cm.
3𝑐𝑚² + 4𝑐𝑚² = 𝐶²
9𝑐𝑚 + 16𝑐𝑚 = 𝐶²
25 = 𝐶² - We want to know C, not C²
5 = 𝐶 - The answer is not right if the hypotenuse is
smaller than one of the sides
, Labeling a Triangle
Hypotenuse - The longest side and opposite the right angle
Opposite - The side opposite the given angle
Adjacent - The side next to the given angle
Sin, Cos, Tan
- Sine SOH
𝑜𝑝𝑝
𝑆𝑖𝑛 = ℎ𝑦𝑝
- Cosine CAH
𝑎𝑑𝑗
𝐶𝑜𝑠 = ℎ𝑦𝑝
- Tangent TOA
𝑜𝑝𝑝
𝑇𝑎𝑛 = 𝑎𝑑𝑗
SOHCAHTOA - To help remember the trigonometric ratios
