I have a triangle the area is 20 what is the area of all the triangle
The area of a single triangle is given by the formula:
Area = (1/2) * base * height
If the area of one triangle is 20, then the total area of all the triangles together will depend on the number of triangles you have.
If you have only one triangle, then the total area is 20.
If you have more than one triangle, then you would need to know the number of triangles and the arrangement in order to calculate the total area.