DAILY INTERACTIVE PUZZLES

matchstick puzzles

The Flounder

Move 3 matchsticks so that the flounder swims in another direction. ____________ *by Serhiy & Serhiy Jr Grabarchuk

COIN PUZZLES

Austria

doubletters

Aug 25, 2026

a
a
a
a
c
c
c
c
e
e
e
e
f
f
f
f
l
l
l
l
r
r
r
r
u
u
u
u
y
y
y
y

Place all double-lettered tiles into the letter line so that a valid word is revealed

PUZZLE CLASSICS

Sphere & Cylinder: Surface Areas

Sphere & Cylinder: Surface Areas

A sphere fits exactly inside a thin-walled cylinder that has a height and the diameter equal to the diameter of the sphere. Let's mark the surface area of the sphere as SA(s) and the lateral surface area (which is EXCLUDING the bases) of the cylinder as LSA(c). How SA(s) is related to LSA(c)?

PUZZLE CLASSICS

PUZZLE CLASSICS

Sphere & Cylinder: Surface Areas

Sphere & Cylinder: Surface Areas

A sphere fits exactly inside a thin-walled cylinder that has a height and the diameter equal to the diameter of the sphere. Let's mark the surface area of the sphere as SA(s) and the lateral surface area (which is EXCLUDING the bases) of the cylinder as LSA(c). How SA(s) is related to LSA(c)?