the lowest row has 198 triangular blocks.For each of the other rows,the number of triangular blocks are 4 more than in the above row.Joe builds a triangular blocks in this way.The number of triangular blocks in the top row is 2.

a)Calculate the number of rows in this arrangement

b)If the height and the base of each triangular block is 6 cm and 8 cm respectively,calculate the area,in cm,of the triangle.