Dot Detective | Mills Maths Tools

MMTMills Maths Tools

Dot Detective

Dot Detective

A grid of dots, and somewhere among them a shape is hiding. Only one set of dots works — find it. Every puzzle has exactly one answer.

Choose a level

🔍

Find the shape.

Tap the dots you think are its corners.

— ✓ 0 solved

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The box method

Things to check

Share this puzzle

Anyone who opens the link gets this exact puzzle. Nothing is saved online.

The paper

Puzzles Level How many (1–12)

Puzzles per page — fewer means bigger grids

Options

Definition under each shape name Working space for area puzzles Answer key Name and date

Every puzzle is checked against every possible choice of dots, so each has exactly one answer.

Dot Detective · Mills Maths Tools

How to play

Find the Shape. Some points on the grid are marked with dots. Exactly one set of them are the corners of the shape named. Tap them — the order does not matter.
Shapes can be tilted. A square does not have to sit flat: count across and up along each side to check the sides are equal and the corners are right angles.
Names mean what the definitions say. A square is also a rectangle, a rhombus and a parallelogram, so a “rectangle” puzzle never has a square hidden in it as well — there is only ever one answer.
Find the Triangle. Choose three dots that make a triangle with exactly the area given. Each grid square is 1 square unit.
For a sloping triangle, draw the box around it, then take away the right-angled triangles in the corners. That is the box method, and the game will show it to you.
Tap a dot again to take it back. Keyboard: Tab to a dot, Enter or Space to choose it.

Settings

Show the definitionWhat the shape has to have, beside its name. Say what a wrong choice makes“Those four dots make a rectangle, not a square.” / “That triangle's area is 4.” Mark equal sides and right anglesAfter a check, tick marks show equal sides and small squares show right angles. Box method helpIn Find the Triangle, a button draws the box around a chosen triangle and works out its area.

Show the answer?

This shows the dots and ends this puzzle.