bantu ya nomer 13 14 15 makasiih jan main main yaa

13. LPbalok = 2[(p×l)+(p×t)+(l×t)]
=> 258 = 2[(p×l)+(p×t)+(l×t)]
=> 258 = 2[(9×5)+(9×t)+(5×t)]
=> 258 = 2(45+9t+5t)
=> 258 = 2(45+14t)
=> 258 = 90 + 28t
=> 258 - 90 = 28t
=> 168 = 28t
=> 168/28 = t
=> t = 6 cm

Vbalok = p×l×t
=> Vb = 9 × 5 × 6
=> Vb = 270 cm³

14. Sisi = n + 2 => Sisi = 7 + 2 = 9 sisi
Rusuk = 3n => Rusuk = 3 × 7 = 21 rusuk
Titik sudut = 2n => Titik sudut = 2 × 7 = 14 titik sudut

15. LPprisma∆ = 2alas + selimut1 + selimut2 + selimut 3

alas = at/2
=> 12×16/2 = 12×8 = 96 cm²

selimut1 = p1 × tp = 12 × 25 = 300 cm²
selimut2 = p2 × tp = 16 × 25 = 400 cm²
selimut3 = p3 × tp = 20 × 25 = 500 cm²

LPp∆ = 2a + s1 + s2 + s3
=> LPp∆ = 2×96 + 300 + 400 + 500
=> LPp∆ = 192 + 1200
=> LPp∆ = 1392 cm²

keterangan :
•LPbalok = Luas Permukaan balom
•p = panjang
•l = lebar
•t = tinggi
•Vbalok = Volume balok
•n = Jumlah rusuk/sisi bangun datar dari prisma
•LPprisma∆ & LPp∆ = Luas Permukaan prisma segitiga
•selimut = bangun datar di antara alas dan tutup dari prisma
•a = alas