Question

. The maximum length of pencil that can be kept in a rectangular box of dimensions

12 cm × 9 cm × 8 cm is [ ]

a) 13 cm b) 17 cm c) 18 cm d) 19 cm​

Answer 1

Answer:

(b) 17cm

Step-by-step explanation:

The maximum length of pencil=diagonal of rectangular box

= root under( l sq.+ b sq. + h sq.)

= root under( 12 sq.+ 9 sq. +8 sq.)

= root under(144+81+64)

= root under(289)

=17cm. Ans.

Answer 2

Before, finding the answer. Let's find out how we can find the answer.

• In this question, we have to find the maximum length of pencil that can be kept in a rectangular box.
• So, to find that, we have to find the Diagonal of the cuboid. To find the Diagonal of cuboid, we must use the formula of :

$\boxed{ \sf Diagonal \: of \: the \: cuboid = \sqrt{l^2+b^2+h^2} }$

______________________________

Given :

• Length = 12 cm
• Breadth = 9 cm
• Height = 8 cm

To find :

• maximum length of pencil

Solution :

Diagonal of cuboid = √l² + b² + h²

                                = √12² + 9² + 8²

                                = √144 + 81 + 64

                                = √289

                                = 17  [17 × 17 = 289]

Therefore, the correct option is (b) 17 cm.