Question

The perimeter of the base of a cuboid is 42cm & height is 9cm. Find the lateral surface area?

Please I beg you from My heart.. Please Find It..

Answer 1

Answer:

378 $cm^{2}$

Step-by-step explanation:

height = 9cm

perimeter = 42 cm

2(l+b) = 42

l+b = 21

lateral surface area = 2(l*h+b*h)  

                                 = 2h (l+b)

                                 = 2 x 9 x 21

                                  = 18 x 21

                                  =378 $cm^{2}$

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Answer 2

Given that,

• Perimeter of the Base of  cuboid = 42 cm

• Height of the cuboid = 9 cm

[we know a cuboid has rectangle as it's base]. so,

• Perimeter of rectangle = 42 cm

⇒ 2(l + b) = 42 cm

⇒ (l + b) = 42 cm/2

⇒ l + b = 21cm ------------------------------ equation - 1

• LSA of the cuboid = 2h( l + b )

⇒ LSA = 2×9cm×(21cm)   ----------------------------- From equation - 1

⇒ LSA =  378 cm².

∴ The LSA of the cuboid is 378 cm².

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