BELLWORK 10-4 Get your workbook and complete: 10.1 (63): 1,3,5, (64): 3,5,11

§10.4, Perimeter and Area in the Coordinate Plane 10-4 I will find the perimeters and areas of figures in a coordinate plane. Learning Target

Perimeter and Area in the Coordinate Plane 10-4 Estimate the area of the irregular shape. Method 1: Draw a composite figure that approximates the irregular shape and find the area of the composite figure.

Perimeter and Area in the Coordinate Plane 10-4 Estimate the area of the irregular shape. Method 2: Count the number of squares inside the figure, estimating half squares. Use a for a whole square and a for a half square.

Perimeter and Area in the Coordinate Plane Draw and classify the polygon with vertices E(–1, –1), F(2, –2), G(–1, –4), and H(–4, –3). Find the perimeter and area of the polygon. Step 1 Draw the polygon. Step 2 EFGH appears to be a parallelogram. To verify this, use slopes to show that opposite sides are parallel. slope of EF = slope of FG = slope of GH = slope of HE =

Perimeter and Area in the Coordinate Plane 10-4 Step 3 Find the perimeter Since EFGH is a parallelogram, EF = GH, and FG = HE.

Perimeter and Area in the Coordinate Plane 10-4 Step 3 Find the area Since EFGH is a parallelogram construct a line to create two triangles, then construct the height of the triangle. The area of EFGH is 2(4.5) = 9 units 2.

Perimeter and Area in the Coordinate Plane 10-4 Draw and classify the polygon with vertices L(–2, 1), M(–2, 3), N(0, 3), and P(1, 0). Find the perimeter and area of the polygon

Perimeter and Area in the Coordinate Plane Find the area of the polygon with vertices K(–2, 4), L(6, –2), M(4, –4), and N(–6, –2). Draw the polygon and close it in a rectangle. Area of rectangle: A = bh = 12(8)= 96 units 2. Subtract out the area of the four triangles The area is 96 – 12 – 24 – 2 – 10 = 48 units 2.

Perimeter and Area in the Coordinate Plane 10-4 Show that the two composite figures cover the same area.

Perimeter and Area in the Coordinate Plane 10-4 Show that the area does not change when the pieces are rearranged. Find the area of each figure and compare. blue triangle: red rectangle: A = bh = 2(5) = 10 units 2 green triangle: bottom rectangle: A = bh = 3(4) = 12 units 2

HOMEWORK: Pg 707, #11,15,17,18…you’ll need graph paper