Left part (a × b)
12
sq units
Right part (a × c)
6
sq units
Whole rectangle
18
sq units
a × (b + c) = 3 × (4 + 2) = 3 × 6 =
18
a×b + a×c = 12 + 6 =
18
▮▮ Pull the two parts apart
↺ Reset
Drag the
brass dot
to change
b
and the
mustard dot
to change
c
; the
grey dot
changes the height
a
. The whole rectangle is
a × (b + c)
— but it's also just the two pieces,
a×b
and
a×c
, added together. That's the whole law.