### Home > CALC > Chapter 3 > Lesson 3.2.3 > Problem 3-74

Write and then compute a Riemann sum to determine the area where

*is the function below. Choose the number of rectangles so that your answer will be a good approximation of the area. What is the name of the shape of which you calculated the area? Confirm the accuracy of the Riemann sum by calculating the area geometrically.*

General form of a left-endpoint Riemann sum:

Hint for choosing the number of rectangles, : While you want to choose a large value for

*, be mindful that you will use that value to compute*

Since

*, it is recommended (though not necessary) that you choose an*

*that is divisible by*

You should have recognized that this function is a semi-circle with center at the origin and radius

Use the eTool below to visualize this problem.

Click the link at right for the full version of the eTool: *Calc 3-74 HW eTool*