1. Measuring Line Segments

2. We can use the properties of a square to find its
area
or even its
side length .
We can calculate the length of any line segment on a grid by thinking of it as the side length of a square!
Let’s try this two ways . . .

3. Example 1: P Q
Use a ruler and a protractor (for 90o angles) to create a square with the segment PQ as one side length.
- the length of PQ is therefore
the square root of the area 

4. Cut the square into four
congruent triangles and
a smaller square.
Find the area of each
triangle with the
formula
What is the area of the smaller square?
Add all of these numbers together to get the total area, then find the square root  which gives you the length of the line segment PQ

5. Example 2: Use the existing grid to draw an enclosing square . . . Be
sure to touch each corner.
Example 2:
Use the area formula to find
the area of the larger square.
The triangles formed by the large
square are congruent. Find their
area with the formula
The area of the large square
minus the area of the four
triangles will leave you with
 the area of the original square 
Find the square root and you will have the length of each side
segment!

6. PRACTICE. . . text p. 20 (7, 8, 9) p. 21 (11, 12) Show your work
Check your answers
Homework: worksheet pkg.