Cosine
Cosine is a trigonometric function that is used to describe the relationship between the angle of a right triangle and the ratio of the length of the adjacent side to the length of the hypotenuse. In a right triangle, the cosine of an angle is calculated by dividing the length of the adjacent side by the length of the hypotenuse.
Formula
The formula for calculating the cosine of an angle θ in a right triangle is:
cos(θ) = adjacent side / hypotenuse
Example
For example, if we have a right triangle with an angle of 30 degrees and the length of the adjacent side is 4 and the length of the hypotenuse is 5, we can calculate the cosine of 30 degrees as:
cos(30°) = 4 / 5 = 0.8
Study Guide
- Understand the concept of a right triangle and how the adjacent side and hypotenuse are related to the cosine function.
- Practice using the cosine function to calculate the value of an angle in a right triangle.
- Learn how to use a calculator or a table of trigonometric values to find the cosine of an angle.
- Understand the properties of the cosine function, such as its range and periodicity.
◂Math Worksheets and Study Guides Fourth Grade. Measurement
Study Guide
Measurement 
Activity Lesson
Comparing Volume Capacities Activity Lesson
Measurement Conversion Cards Activity Lesson
Temperature - Reading Thermometers Worksheet/Answer key
Measurement Worksheet/Answer key
Measurement Worksheet/Answer key
Measurement Worksheet/Answer key
Measurement Worksheet/Answer key
Measurement Worksheet/Answer key
Measurement Worksheet/Answer key
Units of Measurement Worksheet/Answer key
Length Worksheet/Answer key
Measurement & Money Crossword Worksheet/Answer key
Measurement Conversions Vocabulary/Answer key
Measurement Vocabulary/Answer key
Measurement Vocabulary/Answer key
Measurement
Activity LessonActivity LessonActivity LessonWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyVocabulary/Answer keyVocabulary/Answer keyVocabulary/Answer keyThe resources above cover the following skills:
Measurement (NCTM)
Understand measurable attributes of objects and the units, systems, and processes of measurement.
Understand such attributes as length, area, weight, volume, and size of angle and select the appropriate type of unit for measuring each attribute.
Understand the need for measuring with standard units and become familiar with standard units in the customary and metric systems.
Understand that measurements are approximations and how differences in units affect precision.
Apply appropriate techniques, tools, and formulas to determine measurements.
Select and apply appropriate standard units and tools to measure length, area, volume, weight, time, temperature, and the size of angles.