Help please, due soon need it

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Measures of the angle of r, 31 s (x+4) t (3x+9)

Atriangle has an area of 72 square inches. if the base of the triangle has a length of 18 inches, what is the height of the triangle? use the formula for the area of a triangle: area = (base)(height) type a numerical answer in the space provided. do not include the units or spaces in your answer.