Plis jawab pake cara!

L.permukaan balok = 2 x (p x l)
2 x (p x t)
2 x (l x t)
= 2 x (42cm x 14 cm) + 2 x (42cm x 18 cm) + 2 x ( 14cm x 18 cm)
=2 x 588 cm² + 2 x 756cm² + 2 x 252cm²
= 1176cm² + 1512cm² + 504cm²
= 3192cm²

[tex]lp \: balok \: = (2 \times p \times l) + (2 \times p \times t) + (2 \times l \times t) \\ = (2 \times 42 \times 14) + (2 \times 42 \times 18) + (2 \times 14 \times 18) \\ = (1176) + (1512) + (504) = 3912 \: {cm}^{2} [/tex]
maaf ya kalo salah