Easy mathematics
2012-01-22 6:40 pm
A metal cube with side 6cm is melted and recast into a cuboid with length 9cm and width 8cm.Find the increase in the total surface area.
回答 (1)
2012-01-22 8:49 pm
✔ 最佳答案
Total volume of the cube:=6 x 6 x 6
=216cm³
Same volume for the recast cuboid
so the height will be
=216 / (8 x 9)
= 3cm
Total surface area of the cube
= 6 x 6 cm² x 6
= 216 cm²
Total suface of the recast cuboid
= 9 x 8 cm² x 2 + 3 x (9 + 8) x 2
= 246 cm²
So the increase in surface area
= 246 - 216cm²
= 30cm²
記得俾分我
收錄日期: 2021-04-16 13:53:33
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120122000051KK00123