# Approximate

Pronunciation: /əˈprɒk.səˌmeɪt/ Explain

To approximate is to find a number close to a real number.[2] Since irrational numbers can not be exactly stated as a decimal, an approximation is used. For example, the value of π is approximately 3.14159. The symbol for writing 'approximately equal to' is ''. For example, π ≈ 3.14159.

One method of approximation is called interpolation. The study of approximation in mathematics is called approximation theory which is a branch of numerical analysis.

### References

1. McAdams, David E.. All Math Words Dictionary, approximate. 2nd Classroom edition 20150108-4799968. pg 18. Life is a Story Problem LLC. January 8, 2015. Buy the book
2. Lambert, P.A., M.A.. Computation and Mensuration. pg 1. www.archive.org. MacMillan and Company. 1907. Last Accessed 6/12/2018. http://www.archive.org/stream/computationmensu00lambrich#page/1/mode/1up/search/approximate. Buy the book

### Educator Resources

• Estimate and Measure. NASA Connect. 2/18/2010. http://www.archive.org/details/NasaConnect-Bhfste-EstimateAndMeasure/index.htm.
• Serving Size Activity. NASA Connect. 2/18/2010. http://www.archive.org/details/NasaConnect-Bhfste-ServingSizeActivity/index.htm.

McAdams, David E. Approximate. 4/11/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. https://www.allmathwords.org/en/a/approximate.html.

### Revision History

4/11/2019: Changed equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)