Virginia SOL Math / Grade 1 / Measurement & Geometry

1.MG.2

Plane Shapes

What you'll learn

  • Name triangles, squares, rectangles, and circles
  • Sort shapes by their number of sides and corners
  • Put shapes together to make new shapes

Words to know

Shape —
a figure with a certain form
Side —
one straight edge of a shape
Corner —
where two sides meet
Triangle —
a shape with 3 sides
Circle —
a round shape with no sides

Why it matters Knowing shapes helps you describe signs, windows, and blocks, and build new shapes from smaller ones.

Worked examples

Model ItI do

How many sides and corners does a square have?

A square has 4 straight sides that are all the same length. Where the sides meet, there are corners. A square has 4 sides and 4 corners.

Try It TogetherWe do

What shape do you get when you put two triangles together along a full side?

Joining two triangles along a matching side makes a shape with 4 sides. A shape with 4 sides can be a square or a rectangle.

Now YouYou do

How many sides does a triangle have?

Count the straight edges of a triangle. Check your answer in the back of this chapter.

Practice

Mastered 0 of 11

Warm-up

Ease in with the basics.

  1. 1.How many corners does a triangle have?

  2. 2.Which shape is round with no sides?

  3. 3.How many sides does a square have?

On Level

The core Quick Check from the book.

  1. 1.How many sides does a triangle have?

  2. 2.How many corners does a rectangle have?

  3. 3.Which shape is round and has no sides?

  4. 4.A shape has 4 equal sides. What is it called?

  5. 5.How many triangles can make one square when cut along a diagonal?

Challenge

Stretch your thinking.

  1. 1.A shape has 4 sides, but only 2 sides are long and 2 sides are short. What is it called?

  2. 2.How many corners do a triangle and a square have all together?

  3. 3.You put two squares side by side along a full side. How many sides does the new shape have?