Angle types poster (free printable angle chart)
Five angle names beside how big each one is, from acute to reflex. Post it beside the protractors and let children match each name to an angle they find in the room.
To save a PDF, choose Print, then “Save as PDF” as the printer. Only the sheet prints.
About this sheet
Angles are named by how much they turn, and the names run in order of size. An acute angle is smaller than a right angle, an obtuse angle is larger but still less than a straight line, and a reflex angle is bigger than a straight line yet less than a full turn. This poster states each size in degrees in plain words, so a child holding a protractor can check a reading against it. The right angle is the anchor: it is the square corner of a page or a door frame, and every other name is compared to it. Edit the text to match your class, for example by adding the full turn of 360 degrees, or by dropping reflex for the youngest group.
Grades: 4 to 8.
How to use it
- Read the five rows aloud and show each with your arms, starting from a right angle at the elbow.
- Print the poster and mount it near the protractors, the geoboards and the dot paper, where angles get drawn and measured.
- Send children to find an angle for each name in the room, sketch it and write its name, then check with a protractor.
Five ideas for class
- Open a pair of scissors slowly and call out acute, right, obtuse as the blades move, so children see an angle change size.
- Look at the clock hands at three, at four and at six, and name the angle each time the hands make.
- Fold a sheet of paper once, then again, to make a square corner, and use it as a right-angle checker around the room.
- Ask partners to estimate an angle in degrees before they measure it, and award a point to whoever is closest.
- Draw a mystery angle on the board, give three clues about its size, and let the class decide its name before you show the protractor.
Related
Questions
Is the reflex angle in my curriculum?
Many standards add it in grade seven or eight. If your class has not met it, delete that line and the poster still shows the other four types correctly.
Why is a straight angle called an angle at all?
It is a turn of exactly half a circle, where the two arms point in opposite directions. It sits between obtuse and reflex in the order of sizes.
How do I help children read a protractor?
Line up the center mark on the corner, and one arm on zero. Then ask whether the angle looks smaller or bigger than a right angle, to pick the correct scale.
How do I save it as a PDF?
Choose Print, then pick “Save as PDF” as the printer. Only the sheet prints: the page around it is hidden. You can also save a sheet as a PNG image under the preview.
Can I print it in black and white?
Yes. Switch to Black and white beside the sheet: fills turn white and lines turn black, so it saves ink and photocopies cleanly.
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