Question

Two spherical pieces of cookie dough have radii of 3cm & 5cm. The pieces are combined to form one large spherical piece of dough. What is the approximate radius of the new sphere of dough?

Answer 1

V 1 = 4/2 · 3³ π = 108/3 π
V 2 = 4/3 · 5³ π = 500/3 π
The new sphere: V = V 1 + V 2 = 608/3 π
4/3 r³ π = 608/3 π / : π/3
4 r³ = 608
r³ = 608 : 4 = 152
r = ∛152
r = 5.3368 cm