The following questions are accompanied by three statements (I), (II), and (III). You have to determine which statements(s) is/are sufficient/necessary to answer the questions.

Perpendicular and base of a right-angle triangle are 5x and 12x respectively. Find the area of right-angled triangle.
I. Perimeter of the right-angle triangle is p cm. 
II. Length of the diagonal side is d cm.

III. Area of another triangle similar to the given triangle is 300 cm².