Be a shape detective
Use attributes to explain shared families and spot a boundary that needs repair.
Explore this lesson →8 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- A quadrilateral is a simple closed shape with four straight sides and four corners. Its sides do not cross. It can have an inward corner.
- A rectangle has four right angles. A rhombus has four equal sides. A square has both, so all three names can fit the same shape.
- Matching side ticks show equal lengths. A small square at a corner shows a right angle. Look for these attributes instead of guessing from the shape's direction.
- A shape can belong to more than one family. Select every matching name, or choose that none of the four fits.
- To draw, choose four dots in order around the boundary, then close it. Use Undo or select a corner and move it with the arrow buttons. Many different drawings can meet the same conditions.
Something to notice
Observe independent drawings and explanations on paper, how a learner checks side equality and square corners, and transfer to unfamiliar orientations or concave boundaries. The API evaluates all supported four-point constructions by exact attributes, not a target outline. Classification, guided controls and independent construction are distinct question types; practice completion is not proof of mastery or retention.
Try it. Change it. Explain it.
Open the lesson to use its pictures and controls. In How it works, connect the picture to the idea. In Play & discover, change the quantities and notice what stays the same. In Your turn, answer questions and use the explanation to check your reasoning.
You can ask for help, draw on the thinking pad, or listen to the question and answer options. Progress distinguishes independent work from work completed with help.
Let’s try it →Curriculum connection
Grade 3 · 3.G · US Common Core
This lesson is mapped to these standards. A completed activity is practice evidence, not a claim of mastery. Content is checked against the linked official standards and its mathematical models are tested.