(a) Here,

As per the question,

We can observe that,

There are in all twelve circles in the box.

And,

We have to shade 1/2 of these circles.

Now,

Since,

12 × = 6

Therefore,

We have to shade 6 circles

(b) Here,

As per the question,

We can observe that,

There are in all nine triangles in the box.

And,

We have to shade 2/3 of these triangles.

Now,

Since,

9× = 6

Therefore,

We have to shade 6 triangles

(c) Here,

As per the question,

We can observe that,

There are in all fifteen squares in the box.

And,

We have to shade 3/5 of these squares.

Now,

Since,

15× () = 9

Therefore,

We have to shade 9 squares