Aphotograph measuring 40 cm by 25 cm is framed up with a uniform margin of width 4 cm all around. find the area of its margin

Area of the margin is 244 cm²

Area = Length x Width

In this scenario, two Areas will be considered to get the area of the margin.

1st set of measurement will be the original measurement of 40 cm by 25 cm.
2nd set of measurement will be the measurement less 4 cm for the margin resulting to 36 cm by 21 cm.

A₁ = 40 cm * 25 cm
A₁ = 1000 cm²

A₂ = 36 cm * 21 cm
A₂ = 756 cm²

Area of the margin = A₁ - A₂
Area of the margin = 1000 cm² - 756 cm² = 244 cm²