Point C (0,p) lies on the y-axis between Q (0,12) and O (0,0) as shown. Determine an expression for the area of triangle ABC in terms of p. Your answer should be simplified as much as possible. Thank you!!
One of the ways to find the area of triangle(ABC) is to find the area of trapezoid(OBAQ) and subtract the areas of
triangle(AQC) and triangle(OBC).
The area of trapeoid(OBAQ) = ½·height·(base1 + base2) = ½·OQ·(OB+ QA) = ½·12·(12 + 2) = 84
The area of triangle(AQC) = ½·base·(height) = ½·AQ·(QC) = ½·2·(12 - p) = 12 - p
The area of triangle(OBC) = ½·base·(height) = ½·OB·(OC) = ½·12·(p) = 6p
Subtracting, we get: triangle(ABC) = trapezoid(OBAQ) - triangle(AQC) - triangle(OBC)
= 84 - (12 - p) - (6p)
You can do the simplifying ...