The length and breadth of a rectangular paper were measured to be the nearest centimeter and found to be 18 cm and 12 cm respectively. Find the percentage error in its perimeter.

To find the percentage error in the perimeter of the rectangular paper, we need to compare the actual perimeter with the measured perimeter.

Let's first calculate the actual perimeter using the given length and breadth of the rectangular paper.

Perimeter = 2 × (Length + Breadth)

Length = 18 cm
Breadth = 12 cm

Actual Perimeter = 2 × (18 cm + 12 cm)
= 2 × 30 cm
= 60 cm

Now, let's calculate the measured perimeter. Since the length and breadth were measured to the nearest centimeter, we can assume that there could be a maximum error of ±0.5 cm in each measurement. Therefore, the measured length and breadth can vary between (18 - 0.5) cm and (18 + 0.5) cm, and (12 - 0.5) cm and (12 + 0.5) cm, respectively.

Measured Length = (18 - 0.5) cm = 17.5 cm
Measured Breadth = (12 - 0.5) cm = 11.5 cm

Measured Perimeter = 2 × (Measured Length + Measured Breadth)
= 2 × (17.5 cm + 11.5 cm)
= 2 × 29 cm
= 58 cm

Now, we can calculate the percentage error in the perimeter by finding the difference between the actual perimeter and the measured perimeter, dividing it by the actual perimeter, and multiplying by 100.

Percentage Error = (|Actual Perimeter - Measured Perimeter| / Actual Perimeter) × 100
= (|60 cm - 58 cm| / 60 cm) × 100
= (2 cm / 60 cm) × 100
= 0.033 × 100
= 3.33%

Therefore, the percentage error in the perimeter of the rectangular paper is approximately 3.33%.