Question

Use the quadrant system to find the area of the polygon

Answer 1

Answer:

The area of the polygon is 64 units²

Step-by-step explanation:

* Lets explain how to solve the problem

- The polygon has 5 sides and 5 vertices

- To find its area by easy way split it into two trapezoid by a horizontal

  line y = 1

- The vertices of trapezoid (1) are (-5 , 1) , (4 , 1) , (-5 , 5) , (0 , 5)

- The vertices of one of the parallel bases are (-5 , 1) , (4 , 1)

- The length of this base = 4 - (-5) = 4 + 5 = 9 units

- The vertices of the other parallel bases are (-5 , 5) , (0 , 5)

- The length of this base = 0 - (-5) = 0 + 5 = 5 units

- The length of its height = 5 - 1 = 4 units

- The area of the trapezoid = 1/2 (b1 + b2) × h

∴ Area of trapezoid 1 = 1/2 (9 + 5) × 4 = 28 units²

- The vertices of trapezoid (2) are (4 , 1) , (-5 , 1) , (-5 , -5) , (-2 , -5)

- The vertices of one of the parallel bases are (4 , 1) , (-5 , 1)

- The length of this base = 4 - (-5) = 4 + 5 = 9 units

- The vertices of the other parallel bases are (-5 , -5) , (-2 , -5)

- The length of this base = (-2) - (-5) = -2 + 5 = 3 units

- The length of its height = 1 - (-5) = 1 + 5 = 6 units

∴ Area of trapezoid 1 = 1/2 (9 + 3) × 6 = 36 units²

∵ Area of the polygon = Area trapezoid (1) + Area trapezoid (2)

∵ Area trapezoid (1) = 28 units²

∵ Area trapezoid (2) = 36 units²

∴ Area of polygon = 28 + 36 = 64 units²

∴ The area of the polygon is 64 units²