Answer:
604.4 cm²
Explanation:
Surface area of a cone = πr(r + √h² + r²)
π = 3.14
r = diameter/2 = 13.4 cm/2 = 6.7 cm
h = 21 cm
Surface area of a cone = πr(r + √h² + r²)
= 3.14 * 6.7(6.7 + √21² + 6.7²)
= 21.038(6.7 + √441 + 44.89)
= 21.038(6.7 + √485.89)
= 21.038(6.7 + 22.04)
= 21.028(28.74)
= 604.3 cm²
Surface area of a cone = 604.4 cm²