3 triangles should be shaded to shape 1/4 of the shape. 3 more triangles should be shaded to shape 1/3 of the shape.
a) In the first shape, there are 12 triangles. So, to shade 1/4 of the shape, we would simply multiply the number of triangles in the shape with 1/4.So,
12*1/4=3 triangles
Therefore, 3 triangles should be shaded to shape 1/4 of the shape.
b) In the second shape, there are 15 triangles. Two triangles are already shaded. So, to shade 1/3 of the shape, we will again multiply the number of triangles in the shape with 1/3. So,
15*1/3=5 triangles
So total of 5 triangles should be shaded to shape 1/3 of the shape. But, 2 triangles are already shaded, so 5-2=3 more triangles should be shaded to shape 1/3 of the shape.