Question

If a parallelogram base is same with the base of a triangle inside the parallelogram, then the area of triangle is half of the area of parallelogram ?

Answer 1

Yes, that's the 3rd or 4th theorem. Any triangle inside the parallelogram having the same base is half of the area of Parallelogram and also the sum of the areas of other two triangles formed would be equal to the middle triangle

Answer 2

Yes because the area of a parallelogram
is equal to half area of triangle