GEOMETRY TUTORIAL
How to Calculate the Area of Circles (Full, Half, and ¾ Circle)
Learn how to find the area of full circles, half circles, and three-fourths of a circle using the correct formula and clear visuals.
Subject hub
Explore Geometry
Explore shape, measurement, area, circumference, volume, and other geometry topics. Begin with a visual tutorial and use practice activities as they become available.
Watch Geometry Tutorials
Start with a clear explanation or browse the complete video collection for this subject.
GEOMETRY TUTORIAL
How to Calculate the Area of Rectangles, Parallelograms, and Triangles
This tutorial walks you through how to calculate the area of rectangles, parallelograms, and triangles—all in one video!
GEOMETRY TUTORIAL
How to Calculate the Circumference of Circles (Full, Half, ¾ Circle)
Learn how to calculate the circumference of a full circle, half circle, and three-fourths of a circle using visual diagrams and step-by-step examples.
Practice Geometry
Work through continuously generated questions and review the tutorial whenever you need help.
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Converting Square & Cubic Units
Convert between square and cubic metric units in Foundation, Core, and Challenge. Number Input or Unit Selection.
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Perimeter of Circle Portions
Calculate the arc and straight-edge lengths of a quarter, half, or three-quarter circle.
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Circumference of Circles
Calculate a circle’s circumference from its radius or diameter using π = 3.14.
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Missing Interior Angles
Find missing interior angles in triangles and quadrilaterals using 180° and 360°.
Area of Circle Portions
Calculate areas of semicircles, quarter circles, and three-quarter circles.
Area of Circles
Calculate areas from whole-number radii, diameters, and decimal measurements.
Surface Area of Cylinders
Choose total surface area, lateral surface area, or Mixed, then progress through Foundation, Core, and Challenge.
Volume of Cylinders
Calculate cylinder volume through Foundation, Core, and Challenge, including radius, diameter, decimal dimensions, and reverse problems.
Vertically Opposite Angles
Progress from direct opposite-angle equality to full intersections and algebraic Challenge problems.
Angles on a Straight Line
Find missing straight-line angles through Foundation, Core, and algebraic Challenge questions.
Area of Triangles & Quadrilaterals
Practice calculating area, converting square units, and working backwards to find missing lengths and heights.
2(lw + lh + wh)
Surface Area of Cuboids
Calculate surface area through Foundation, Core, and Challenge modes, including missing-face reasoning and square-unit conversions.
dm³ ↔ L
Converting Between Cubic Units and Liters
Practice converting between cubic units and liters through Foundation, Core, and Challenge modes.
More Geometry practice activities coming soon.