Question

4. The surface area of a cuboid is 2350 cm? If its length and breadth are 25 cm and 20 cm respectively, find its
height
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Answer 1

→Question: The surface area of a cuboid is 2350cm². If its length and breadth are 25 cm and 20 cm respectively, find its  height?

⇔Given:

• Total surface area of cuboid = 2350cm²
• Length of cuboid = 25cm
• Breadth of cuboid = 20cm

⇔To find:

• Height of the cuboid = ?

⇔Solution:

⇒We know, total surface area of cuboid = 2(lb+bh+hl)

• 2(lb+bh+hl) = 2350
• lb+bh+hl =   ²³⁵⁰⁄₂
• lb+bh+hl =  1175

⇒Where:

• l  = 25cm
• b = 20cm

• lb+bh+hl = 1175
• 25×20+20×h+25×h = 1175
• 500 + 45h = 1175
• 45h = 1175 - 500
• 45h = 675
•  h    =  ⁶⁷⁵⁄₄₅
•  h    =  15cm

∴The height of the cuboid with:

• total surface area 2350cm²
• length 25cm
• breadth 20cm  

is 15cm.

Answer 2

2(lb+bh+hl) = 2350

lb+bh+hl =   ²³⁵⁰⁄₂

lb+bh+hl =  1175

⇒Where:

l  = 25cm

b = 20cm

lb+bh+hl = 1175

25×20+20×h+25×h = 1175

500 + 45h = 1175

45h = 1175 - 500

45h = 675

h    =  ⁶⁷⁵⁄₄₅

h    =  15cm

∴The height of the cuboid with:

total surface area 2350cm²

length 25cm

breadth 20cm  

is 15cm.