Question

Find the expenses of painting a blackboard of length 10m and breadth 8 m at the rate Rs 42 per square meter.​

Answer 1

Answer:

3560 Rs.

Step-by-step explanation:

A.O.R = l× b

           = 10 ×  8

   =80

80× 42=3560

Answer 2

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$\large{\green{\underline \bold{\tt{Given :-}}}}$

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• Length of blackboard is 10m

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• Breadth of blackboard is 8m

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• Rate of painting is Rs 42 per sq. m

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$\large{\red{\underline \bold{\tt{To \: Find :-}}}}$

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• The cost of painting the blackboard

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$\large{\orange{\underline{\tt{Solution :-}}}}$

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As blackboard is in the shape of rectangle.

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$\underline{\bold{\texttt{Area of rectangle :}}}$

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➠ Length × Breadth

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$\underline{\bold{\texttt{Area of blackboard :}}}$

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• length = 10m

• breadth = 8m

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➜ 10 × 8

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➨ 80 sq. m

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Hence area of rectangular blackboard is 80 sq. m

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$\underline{\bold{\texttt{Cost of painting :}}}$

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➠ Rate of painting = Rs 42 per sq. m

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➜ Cost = Area × Rate per sq. m

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➜ Cost = 80 × 42

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➨ Cost = Rs 3360

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• Hence expense of painting the blackboard at the rate Rs 42 per square meter is Rs 3360

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Additional information

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• Perimeter of rectangle = 2(length + breadth)

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Properties of rectangle

• The opposite sides are parallel and equal to each other.

• Each interior angle is equal to 90 degrees.

• The sum of all the interior angles is equal to 360 degrees.

• The diagonals bisect each other.

• Both the diagonals have the same length