Tolong dong besok dikumpulkan. Sama caranya yah yg detail. Makasih

3. L = phi × r²
= 3.14 × 40²
= 3.14 × 40 × 40
= 3.14 × 1600
= 5024 cm²
k = 2.phi × r
= 2× 3.14 × 40
= 3.14 × 80
= 251,2 cm

maaf banget klau salah yaa