Can someone show how to do this please

77 units^2

Step-by-step explanation:

I'm going to call the red square A, green square B, blue square C.

A side of a square is the square root of the area.

The Pythagorean Theorem is A^2 + B^2 =C^2.

So in other words,  

33 + 44 = the side of square C^2.

33+44=77

One side of square C is √77.

Square this to get the area.

Square C's area is 77 units^2.

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step-by-step explanation:

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