tolong bantu + caranya juga. makasih

Pertama, dicari diagonal bidangnya
d^2 = 40^2 + 30^2
d^2 = 1600 + 900
d^2 = 2500
d = √2500
d = 50 cm

L arsiran = diagonal bidang x lebar balok
= 50 x 10
= 500 cm^2
= 5 dm^2 (A).

*semoga membantu. sukses selalu ^_^

diagonal = √40²+30³ =√1600+900=√2500=50 cm

L = 50 x 10 = 500 cm² = 5 dm²

jawab.A