24. diketahui = K = 280 cm , l = 55 cm ditanya = p ? jawab = rumus keliling persegi panjang = 2 × ( p + l ) = ( 280 ÷ 2 ) - 55 = 140 - 55 = 85 cm { B. }
25. kerucut { D. }
26. luas permukaan = 2 × ( p × l + p × t + t × l ) = 2 × ( 21 × 8 + 21 × 15 + 15 × 8 ) = 2 × ( 168 + 315 + 120 ) = 2 × 603 = 1206 { A. }
3/4 × phi × j × j
3/4 × 22/7 × 35 × 35
3/4 × 22 × 5 × 35
3/4 × 3.850 cm2
2.887,5 cm2 { B. }
23.
bangun 1 = persegi panjang, p× l = 10 × 36 = 360 cm2
bangun 2 = trapesium, 1/2 (a+b) × t = 1/2 (24+36) × 18
= 1/2 . 60 × 18 = 30 × 18 = 540 cm2
1 + 2 = 360 + 540 = 900 cm2 { D. }
24.
diketahui = K = 280 cm , l = 55 cm
ditanya = p ?
jawab = rumus keliling persegi panjang = 2 × ( p + l )
= ( 280 ÷ 2 ) - 55 = 140 - 55 = 85 cm { B. }
25. kerucut { D. }
26.
luas permukaan
= 2 × ( p × l + p × t + t × l )
= 2 × ( 21 × 8 + 21 × 15 + 15 × 8 )
= 2 × ( 168 + 315 + 120 )
= 2 × 603 = 1206 { A. }