Question 10 • (OC27) GEO-1206310-S2-Degele-VOL7006P
Cutting the cylinder lengthwise makes a half-cylinder with radius 4 cm and length 20 cm. Its curved surface area is half the original cylinder’s lateral area: π × 4 × 20 = 80π cm²; the flat rectangular face is 8 × 20 = 160 cm². The two semicircular ends together make one full circle with area π × 4² = 16π cm², for a total of (96π + 160) cm², choice B.
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