How many triangles are there in the following figure?

Let's add all the number of triangles to find out the total number of triangles;

01+02+03+04+05+06+07= 28 total number of triangles in the given figure.

Or,

We can use the formula of "Sum of natural numbers" which is; n(n+1)/2

Therefore, 7(7+1)/2 =  \(\frac{56}{2}\)= 28 number of triangles.