PC Cell Efficiency: Find Power (in W)

[rosie_burk]

Homework Statement

A photovoltaic cell has area 80 sq cm and efficiency converting energy in the form of sunlight to electricity of 7%. The sun's intensity is 800 W / sq m and the rays are perpendicular to the cell's surface.
What power will be produced by this cell (in W)? Take care in converting to SI units.

Homework Equations

=(intensity)(area)

The Attempt at a Solution

80*10^-2 *.07 * 800 = 44.8

but the back of the books says the answer is .45

 

[kuruman]

1 cm = 10^-2 m

(1 cm)² = (10^-2 m)² = ?

Cheers.