Rumus volume: s³ = s × s × s

a.) s³

= 5 × 5 × 5

= 25 × 5

= 125 cm³

Rumus luas permukaan kubus: 6(s²) = 6(s × s))

b.) 6s²

= 6(5 × 5)

= 6(30)

= 180 cm²

c.) Panjang AC (diagonal bidang):

AC² = AB² + BC²

AC = √(5²) + (5²)

AC = √25 + 25

AC = √50

AC = √25 × 2

AC = √25 × √2

AC = 5√2

d.)Panjang EC (diagonal ruang):

EF² = AC² + AE²

EF = (5√2)² + 5²

EF = 50 + 25

EF = √75

EF = √25 × 3

EF = √25 × √3

EF = 5√3

e.) Rumus mencari panjang rusuk kubus: 12 × s

Kubus terdiri atas 12 rusuk: AB, BC, CD, AD, EF, FG, GH, EH, AE, BF, CG, DH

12 × s

= 12 × 5

= 60

f.) Rumus luas bidang diagonal: s²√2 = s × s√2

s²√2

= 5²√2

= 5 × 5√2

= 25√2