∵ The 2 cell phones are proportional
∴ Their dimensions are proportional

∵ l1 = 5.4 in and l2 = 6.21
∵ w1 = 2.6 in and w2 = ?
Substitute them in the ratio above

By using cross multiplication

Divide both sides by 5.4

The width of the larger cell phone is 2.99 in
The answer is C