Warm up

3 4

5

A farmer knows he needs to grow an area of 81 km2 of corn to make a profit. His field is a square. How long are the sides of his corn field?

Warm up correction

Homework correction

So, what is

a ratio

nal number a

gain?

Are the following numbers rational?Why?

-7/10

-12

2.34

0.666....

0.172458917245891724589....

So, are all numbers rational then?

Square root of a number

Square of a number a:

The number times itself : axa = a2

Examples:

Square root of a positive number b:

·a number c so that c2= b

·Each positive number has a positive and negative square root

·The notation for the positive square root of a number is √

Example:

Perfect squares

Applications with partner