# 7.9. Chapter Exercises¶

Fix the errors so it runs and returns the perimeter of a rectangle.

The `areaTriangle`

function below was hard coded so it always uses 5 and 4 for the base and
height of a triangle to calculate the area for. Modify the function so that it has parameters
for base and height and works to calculate the area of different triangles.

The mathemetician Newton invented a method to approximate the square root of a number.
Take the number **N** you want the square root for and a guess **G** and then
calculate \(1/2(N/G + G)\). You will get a rough approximation. If you use the
answer as a new guess and repeat the process, you will get a closer approximation. You
can keep repeating the process to make your approcimation closer and closer to the real
value.

Write an `approximateSqrt`

function that takes a number and guess as its parameters
and then uses Newton’s formula to estimate the square root of the number.

There is already code provided to use your function to calculate the square root of 150.