courses › Geometry

Rectangles, triangles, trapezoids, and shapes made of them.

In your head, jot if needed · no calculator why?

Learn first (about 3 minutes)

Opens at level 17.

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Builds on: Bigger multiplication (not open yet)

skills · practice stats

From rounds of this course only: box, review and trial answers are left out. Once a skill has 40 tries, it compares your first 20 tries with your last 20.

• Rectangles par 10 s not tried yet

  worked example

  A rectangle is 6 ft by 14 ft. What is its perimeter in feet?

  Answer: 40

  1. Perimeter = 2 × (6 + 14) = 2 × 20 = 40 ft.

• Triangles & trapezoids par 16 s not tried yet

  worked example

  A triangle has a base of 28 cm and a height of 7 cm. What is its area in square centimetres?

  Answer: 98

  1. Area = ½ × base × height = ½ × 28 × 7 = 98 cm².

• Composite shapes par 25 s not tried yet

  worked example

  An L-shaped garden is a 15 ft × 20 ft rectangle with a 3 ft × 6 ft corner cut out. What is its area in square feet?

  Answer: 282

  1. Whole rectangle minus the missing corner: 15 × 20 − 3 × 6 = 300 − 18 = 282 ft².

rest ladder

Win 3 of your last 4 rounds and the course rests. A win is 90% right, within 2× the round's par. Pass the review when it comes back and the next rest is longer.

1. 1 day
2. 3 days
3. 7 days
4. 14 days
5. 30 days
6. 60 days
7. mastered · every 90 days

your rounds

No rounds yet.