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Course Updates for Basic Geometry in July 2021


We are excited to share that we've made significant enhancements to our Basic Geometry course. One consequence of adding this new content is that it may impact learners’ Mastery percentages.

When we add new content and remove old content, Mastery percentages often change because the number of available skills changes. For example, if you mastered 90 out of 100 skills in a course, and we added 10 new skills, your mastery skill count would then be 90 out of 110. This change would change your Mastery percentage from 90% to 82%.

With this specific course update, we expect that Mastery percentages will change by a maximum of 30%. Most people will see a much smaller Mastery percentage change.

You can see exactly what content items we’ve added and removed below. Happy learning! 

Content Added


Decompose figures to find volume practice

Metric units of length review (mm, cm, m, & km)

Metric units of mass review (g and kg)

Metric units of volume review (L and mL)

Scale drawing word problems


Area & perimeter of rectangles word problems

Area and the distributive property

Circumference of parts of circles

Compare area and perimeter

Compare area with unit squares

Construct scale drawings

Convert to smaller units (g and kg)

Convert to smaller units (mL and L)

Convert to smaller units (mm, cm, m, & km)

Convert units (metrics)

Convert units word problems (metrics)

Corresponding sides and points

Create equations to solve for missing angles

Cross sections of 3D objects (basic)

Decompose angles

Decompose figures to find area

Decompose figures to find volume

Determine rotations (basic)

Distance between points in first quadrant

Distance between points: vertical or horizontal

Estimate mass (grams and kilograms)

Estimate volume (milliliters and liters)

Estimating length (mm, cm, m, km)

Finding missing angles

Identify points

Identify scale copies

Identify scale factor in scale drawings

Metric conversions word problems

Perimeter word problems

Represent rectangle measurements

Rotate points (basic)

Scale copies

Triangle side length rules

Use Pythagorean theorem to find area

Volume word problems

Word problems with mass

Word problems with volume


Area & perimeter word problem: dog pen

Area & perimeter word problem: table

Area and the distributive property

Comparing areas and perimeters of rectangles

Comparing areas word problem

Construct a right isosceles triangle

Convert liters to milliliters

Converting metric units of length

Converting units: centimeters to meters

Converting units: metric distance

Corresponding points and sides of scaled shapes

Creating scale drawings

Decomposing an angle

Decomposing angles

Decomposing shapes to find area: add

Decomposing shapes to find area: grids

Decomposing shapes to find area: subtract

Equation practice with complementary angles

Equation practice with supplementary angles

Equation practice with vertical angles

Find measure of angles word problem

Find measure of vertical angles

How to convert kg to mg and T to oz

Identifying corresponding parts of scaled copies

Identifying scale copies

Identifying scale factor in drawings

Identifying values in scale copies

Interpreting a scale drawing

Interpreting plotted points

Intro to quadrilaterals

Isosceles & equilateral triangles problems

Making a scale drawing

Measurement word problem: tea party

Measures of angles formed by a transversal

Metric system: units of distance

Multi-step unit conversion examples (metric)

Perimeter word problem: skating rink

Perimeter word problem: tables

Pythagorean theorem with isosceles triangle

Radius & diameter from circumference

Slicing a rectangular pyramid

Time word problem: Susan's break

Triangle inequality theorem

U.S. customary and metric units

Understanding mass (grams and kilograms)

Understanding volume (liters)

Volume in unit cubes by decomposing shape

Volume of rectangles inside rectangles

Volume of triangular prism & cube

Volume through decomposition

Volume word problem: gold ring

Volume word problem: water tank

Word problems with mass

Word problems with volume


Content Removed


Graphing coordinates review

Parallel and perpendicular lines review

Quadrilateral problems on the coordinate plane

Translations intro

Vertical angles review

Volume formulas review


Analyze shapes

Analyze shapes by angles

Area of rectangles with partial arrays

Area of right triangles

Area of trapezoids

Benchmark angles

Classify shapes

Classify triangles by side lengths

Compare shapes

Complementary and supplementary angles (no visual)

Constructing triangles

Determine rotations

Dilate points

Dilations and properties

Dilations: center

Draw parallel and perpendicular lines

Equal parts of circles

Equal parts of rectangles

Find missing length when given area of a parallelogram

Find missing length when given area of a triangle

Find perimeter when a side length is missing

Find surface area by adding areas of faces

Identify geometric solids (3D shapes)

Identify parts of 3D shapes

Identify quadrilaterals

Identify shapes

Name shapes 3

Ordering triangle sides and angles

Partitioning rectangles

Quadrants on the coordinate plane

Quadrilateral problems on the coordinate plane

Reflect points

Reflecting points in the coordinate plane

Rotate points

Translate points

Types of angles by measure

Use area of squares to visualize Pythagorean theorem

Volume with cubes with fraction lengths


Another Pythagorean theorem proof

Area of kites

Area of trapezoids

Bhaskara's proof of the Pythagorean theorem

Coordinates of a missing vertex

Coordinates of rectangle example

Counting faces and edges of 3D shapes

Cousin Fal's shape collection

Dilations and properties

Dilations: center

Dimensions of a rectangle from coordinates

Drawing parallel line segments

Equal parts of circles and rectangles

Example of shapes on a coordinate plane

Finding circumference of a circle when given the area

Finding distance with Pythagorean theorem

Garfield's proof of the Pythagorean theorem

Intro to quadrilateral

Ordering triangle sides and angles example

Partitioning rectangles

Points and quadrants example

Pythagorean theorem proof using similarity

Quadrants of the coordinate plane

Recognizing common 3D shapes

Recognizing shapes

Reflecting points in the coordinate plane

Shapes and angles

Translating points

Volume with fractional cubes