Answer:
3299 mm²
Step-by-step explanation:
A=πr(r+√(h²+r²))
h = 20
r = 21
A = π(21)(21 + √(20²+21²) = 3298.672286
400，000，000，000
2*2=4
and 5 zeros plus 6 zeros equals 11 zeros.
try b=32
22
