Question

3 darma is edging a tablecloth with lace. the tablecloth is 210 cm by 180 cm. how much lace does she need?

Explanation:

Step1: Identify the shape and formula

The tablecloth is a rectangle. The length of lace needed is the perimeter of the rectangle. The formula for the perimeter \( P \) of a rectangle is \( P = 2\times (l + w) \), where \( l \) is the length and \( w \) is the width.

Step2: Substitute the values

Given \( l = 210 \) cm and \( w = 180 \) cm. Substitute these values into the formula:
\( P = 2\times(210 + 180) \)
First, calculate the sum inside the parentheses: \( 210+180 = 390 \)
Then, multiply by 2: \( 2\times390 = 780 \)

Answer:

780 cm