1. (25%) If a triangle plane of height d and base b is vert C. Calculation liquid surface a distance (i.e., depth) of h (as shown in the figure below). (1) Please calculate the differential form of this triangle. For instance, the differential area of a circle is rard (5%) 2) Please derive to obtain the depth to its centroid of area; (10%) 3) Please derive to obtain the depth to its center of pressure. (10%)