### Our class is starting a new mathematics unit about geometry and measurement called Perimeter, Area, and Polygons. During this unit, students measure length by using U.S. standard units (inches, feet, yards) and metric units (centimeters, meters). They investigate characteristics of triangles and quadrilaterals (4-sided polygons). They use right angles as a reference to identify other angles as being greater than or less than 90 degrees. Students solve problems about perimeter (the length of the border of a figure) and area (the measure of how much flat space a figure covers).

Benchmarks Examples
Measure and find the perimeter of 2-D figures using U.S. standard and metric units.

What is the perimeter of this photograph?

The bottom will measure the same as the top and the right side will measure the same as the left side.

6 + 4 + 6 + 4 = 20

The perimeter of the photograph is 20 inches.

Find the area of 2-D figures using U.S. standard and metric units.

What is the area of this figure?

I counted 7 square units and two 1212 1 halfsquare units, so the total area is 8 square units

Benchmarks Examples
Categorize quadrilaterals, including squares, rhombuses and rectangles, based on their attributes.

Which of these are quadrilaterals? Explain how you decided.

A, C, and E are quadrilaterals. They all have 4 straight sides.

Which are rhombuses?

A and C are rhombuses.