∵∠ACB=90°,∴AC²+BC²=AB²,
S阴影=1/2π(1/2AC)²+1/2π(BC/2)²+SΔABC-1/2π(1/8AB)²
=1/8π(AC²+BC²-AB²)+1/2×8×6
=24平方厘米.
S阴影=SΔABC.