no 40 dong gais,tolong kasi tau diketahui,cara,rumusnya MAKASII,BUTUH SEGERAAA

Bangun Ruang

39. alas prisma belah ketupat

tinggi = T = 20 cm

alas d1 = 12 cm dna d2 = 16
1/2 d1 = 6
1/2 d2 = 8
s² = 6²+8²---> s = 10  cm
t = 20 cm

Luas permukaan = 2 x luas alas +   keliling alas x tinggi
LP = 2(1/2 d1 d2) + 4(s)(t)
LP = 2(6)(8)  + 4(10)(20)
LP = 96 + 800
LP = 896 cm²

40. ALas prisma segitga sama kaki
a= 18,--> 1/2 a = 1/2 (18)= 9
b = c = 15
t segitiga = √(c² - (1/2 a)² = √(15² - 9²)= 12

Luas prisma = 2 luas alas + keliling alas x tinggi  prisma
LP = 2 (1/2 a t) + (a+b+c)((ts)
LP = 2(1/2)(18)(12) + (18+15+15)(20)
LP = 216 + 960
LP =1.176 cm²

41. Limas persegi
V = 4.000 cm³
t = 30 cm
V = 1/3 luas alas tinggi
4.000 = 1/3 (s²)(30)
10 s² = 4000
s² = 400
s= 20 cm