**16**

The rectangles have area of 14 and 56, they have same base so heights will be 14:56=1:4

Lets say they have sides of 1 unit and 4 unit

If bases of blue and red triangles are a and b their area will be 4a/2 and 5b/2

Since the angle opposite to a & b is same, we have a/4=b/5 -->a=4b/5

Now if we subtract the area of blue triangle from the area of red triangle: 5b/2-2a=9 => 5b/2-2*4b/5=9 => b=10 => a=8

Blue triangles area is 2a=**16**