Question

Va roggg urgent!!!!...​

Answer 1

r-raza disc = 5 m

ABCD -patrat cu latura AB = 2·r = 10 m

diagonala patratului este BD = AB·√2 = 10√2 m

EF-diagonala suprafetei de tabla

EF = ED + DB + BF = r + BD + r = 2·r + BD = 10 + 10√2 = 10·(1+√2)

a) Aria suprafetei de tabla este S = π·(EF/2)² = π·[10/2·(1+√2)]² = π·[5·(1+√2)]² = π·5²·(1+√2)².

b) aria suprafetei inlaturate: S - 4·( π·r²) = π·5²·(1+√2)²- 4·π·5² = π·5²·[(1+√2)²-4] = π·5²·(1+2+2√2-4) = π·5²·(2√2-1)

c) 100·( 4·π·r²)/S = 100·( 4·π·5²)/[π·5²·(1+√2)²] = 400/(1+√2)² ≅ 400/(1+1,41)² = 400/5.8081 ≅ 68.86 %