Question

the diagram shows the length and width of a cell phone, and the length of a larger version of the same brand of cell phone. the lengths and widths of the two cell phones are proportional. what is the width, in inches, of the larger version of the cell phone? a 1.15 b 2.26 c 2.99 d 3.41

Explanation:

Step1: Set up proportion

Since lengths and widths are proportional, \(\frac{\text{Length}_1}{\text{Width}_1}=\frac{\text{Length}_2}{\text{Width}_2}\). Let \(x\) be the width of the larger phone. So \(\frac{5.4}{2.6}=\frac{6.21}{x}\).

Step2: Cross - multiply

\(5.4x = 2.6\times6.21\). Calculate \(2.6\times6.21 = 16.146\). So \(5.4x=16.146\).

Step3: Solve for \(x\)

\(x=\frac{16.146}{5.4}\). \(16.146\div5.4 = 2.99\).

Answer:

C. 2.99