Respuesta :

The side lengths are 1/9 and 1/7 because there are 9 and 7 tiles going along each side of the whole box

The area is 1/63 because 1/9 x 1/7 = 1/63

The area of the shaded rectangle is 40/63
40 (the number of small boxes in the big box) x 1/63 = 40/63