ELLIPSES
Drag to draw

An ellipse is formed by points where the sum of distances to two foci is constant.

Grab the pink point and trace the shape entirely!

d₁ + d₂ = {{ s1_sum.toFixed(1) }}
Slide to match

Match the target ellipse by changing the denominators.

x²: {{ s2_a * s2_a }}
y²: {{ s2_b * s2_b }}
Drag to place

Place the two foci () in their correct locations.

Correct! The distance c to the focus satisfies c² = |a² - b²|.
Hint: The distance from the center to a focus is c. Check the major axis!
Tap to build

Construct the equation for this ellipse.

{{ s4_slots[0] || '?' }}
+
{{ s4_slots[1] || '?' }}
= 1
🎉

Masterful!

You've unlocked the secrets of the ellipse, from foci to equations!