3.1415926535897932384626433832795028841971693993751058209749
445923078164062862089986280348253421170679821480865132823066
4709384460955058223172535940812848111745028410270193852110555964462294895493038196
3383279502884197169399375105820974944592307816406286208998628034825342117067982148086
The π Mystery
Talet pi
π
Math1 of 1 in the world
Discovered 1650 BC · Archimedes
SPARKONNo. 1 / 1
3.1415926535897932384626433832795028841971693993751058209749
445923078164062862089986280348253421170679821480865132823066
4709384460955058223172535940812848111745028410270193852110555964462294895493038196
3383279502884197169399375105820974944592307816406286208998628034825342117067982148086
The π Mystery
π
The ideaEvery circle in the universe, from a coin to a planet's orbit, goes round exactly π times its width.
π = C ÷ d = 3.14159…
Lets you predictThe way round any circle, from one straight measurement.
The only oneBrushed metal, gold-foil π, digits round the edge. Hidden in one random booster pack.
Scan for the full explanation and a practice question.
SPARKON · No. 1 / 1
Flip the card (click, tap, or Enter / Space)

Math π Mystery: planned 1-of-1 physical card

The π Mystery

Swedish: Talet pi · Discovered: Egypt and Babylon, about 1650 BC · pinned down by Archimedes, about 250 BC

Every circle in the universe, from a coin to a planet's orbit, goes round exactly π times its width.

π = C ÷ d = 3.14159…

Why it works

Measure round a plate, then across it. Divide. You get a little over 3. Do it with a bike wheel, a lake, the orbit of the Moon: the same number every time. That number is π.

Its digits never end and never repeat: people have worked out trillions of them and found no pattern. That was proved in 1761. So every circle hides a number nobody will ever write down in full.

The π card is the SparkON mystery card. The full product plan is one physical card only: brushed metal, with π in real gold foil and its digits running round the edge, hidden in one random booster pack. Serial-number registration on this site is planned and not available yet.

What it lets you predict

The way round any circle, from one straight measurement.

How tests ask about it

  • Circumference and area of a circle
  • Why π never ends

Try it

A bicycle wheel is 70 cm across. How far does the bike roll in one full turn of the wheel?

Show the answer

C = π · d = 3.14 × 70 ≈ 220 cm, so about 2.2 m.

Connects to

Pythagoras' theorem

Wins these Lab Duel challenges

  • Not in the first challenge set yet.