Area and perimeter

Area and perimeter help us measure the size of 2D shapes. We’ll start with the area and perimeter of rectangles. From there, we’ll tackle trickier shapes, such as triangles and circles.

Transition from counting unit squares to multiplying side length to find area. Measure side lengths with a ruler to find area. Find area of rectangles by multiplying side lengths. Find a missing side length of a rectangle when given the other side length and area.

Have you ever wondered how much fencing you need to surround a plot of land? No? Well, you should still go through this tutorial just in case. You'll learn what perimeter is and how to calculate it.

A circle is at the foundation of geometry, and at the foundation of a circle is a special number called Pi. This number allows us to relate the radius, diameter, and circumference of a circle.