The measure of length and breadth of a rectangle are l = (30.0 ± 0.2) cm and b = (10.0 ± 0.1) cm. What is the percentage error in the calculation of area of rectangle?

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The measure of length and breadth of a rectangle are l = (30.0 ± 0.2) cm and b = (10.0 ± 0.1) cm. What is the percentage error in the calculation of area of rectangle?


 Length = 30.0 ± 0.2 cm
Breadth = 10.0 ± 0.1 cm

Area  = Length × Breadth  
= (30.0 × 10.0)
= 19.38 cm²

ΔA = A × (ΔL/L + ΔB/B)
= 300.00 × (0.2/30.0 + 0.1/10.0)
= 5 cm²

Area of rectangle = (300.00 ± 5.0) cm²
percentage error in the calculation of area of rectangle
= ΔA/A × 100 
= 5/300 × 100 
= 1.67%

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