Hello, donnagirl!

Another approach . . . same answer.

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The sides and diagonals of divides into __eight__ congruent triangles.

Since is composed of __four__ of these triangles,

. . the area of is one-half of

That is, each square has __half__ the area of the preceding square.

has a perimeter of 40 inches; its side is 10 inches.

. . Its area is: . inē

Then the total area is: .

. .

The geometric series has the sum: .

. . Therefore: .