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20 10 detailed explanation of mathematics problems in Nanning senior high school entrance examination 17
The answer is 49/9;

Let OA 1=a, then the coordinates of A 1, A2 and A3 are: (a, 0)(2a, 0)(3a, 0) respectively.

Then the coordinates from y=8/x, C 1, C2 and C3 are (0,8/a) (0,8/2a) (0,8/3a) respectively.

Then the area of the first shadow (from left to right) is the area of the triangle OC 1B 1, and the formula is: 1/2*a*(8/a)=4.

The area of the second shadow is a quarter of the area of the triangle OC2B2 (as shown in OA 1=A 1A2), and the formula is:1/2 * 2a * (8/2a) * (14) =1.

The area of the third shadow is one-ninth of the area of the triangle OC3B3 (as shown in OA 1=A 1A2=A2A3), then the formula is:1/2 * 3A * (8/3A) * (1/9) = 4/9.

The answer is: 4+ 1+4/9=49/9.

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