A Triangle bounded by the lines y = 0, y = 2x and y = -0.5x + k, with k positive, is equal to 80 square units. What is k?

Answer 1

Draw and label a diagram!

2x = -0.5x + k

2.5x = k

x = k / 2.5

y = 2k / 2.5

Point of intersection, vertex of triangle is (k /2.5, 2k / 2.5)

0 = -0.5x + k

0.5x = k

x = k / 0.5 This is the x-intercept

80 = (0.5)(k / 0.5)(2k / 2.5)

Can you solve for k and answer?