Shapes with Fractional Side Lengths

The irregular shape can be broken into a triangle and a rectangle as shown. Which expression could be used to determine its area?

(0.5)(10)(4.2) + (10)(3.2)

Which expression could be used to determine the area of the square?

(10.75) squared

Which expression could be used to determine the area of a rectangle with a length of 3.5 cm and a width of 0.25 cm?

(3.5)(0.25)

Which expression could be used to determine the area of the triangle shown?

1/2(12 1/3)(3)

A border for a decorative mirror is made with 20 triangular tiles. Each tile has a base of 0.5 cm and a height of 3 cm. What is the total area of the border?

15 cm squared

Instruction: What is the area of the rectangle?

15m squared

What is the area of a rectangle with a base of 12 mm and a height of 1.4 mm?

16.8 mm squared

The area of a rectangular baking sheet is 25 square inches. The base of the sheet is 10 inches. What is the height?

2 1/2 in

The irregular figure can be broken into a triangle and a rectangle as shown with the dashed line. The length of b, the base of the triangle, is ____ ft. The area of the triangle is ___ ft squared. The area of the rectangle is ___ft squared. The area of the irregular figure is ft squared.

2 2/3 4 6 2/3 10 2/3

What is the area of the figure?

25 1/6yd squared

Students are making finger puppets for a puppet show. The figure shown is used as a pattern for a puppet's shirt. What is the area of the pattern? The area is ____ square inches.

3

Gabriel started to calculate the area of the triangle. His work is shown. A = 1/2 bh=1/2 (1/2) (3/4) What is the area of the triangle? The area of the triangle is ___in.²

3/16

What is the area of the figure?

38.8 square meters

If the base of the triangle decreased from 2 yards to 1 yard, what would be the difference in the area?

5/16 yd squared

What is the area of a square that has a side length of 2.8 inches?

7.84 sq in

What is the area of the parallelogram?

8.4cm squared

Stefan's neighborhood has a community garden. The garden has 15 equally sized rectangular plots for people to grow fruits and vegetables. Each rectangular plot measures 8 feet by 10 2/5 feet. What is the area of each plot? Of the garden? The area of each plot is ___ ft squared The total area of the garden is ____ft squared.

83 1/5 1248

How can you break up the figure into familiar shapes to determine the area?

Break up the figure into a 2 ft by 3 2/3 ft triangle and a 5 ft by 1/3 ft rectangle.

How can you break up the figure into familiar shapes to determine the area?

Break up the figure into a 4 m by 5.2 m rectangle and a 3 m by 6 m rectangle.

Magda saw a triangular sign with a base of 4 feet and a height of 2.8 feet. She reasoned that if she first divided each dimension by 2 before multiplying them together, she would get the right area. Is she correct? Explain.

Sample Response: No, Magda is incorrect. The actual area is 0.5(4)(2.8) = 5.6 ft squared. With Magda's method, the area would be (2)(1.4) = 2.8 ft squared

What is the area of the figure? Explain the steps you take to calculate the area.

Sample Response: The area is the sum of the square area and the triangle area. The area of the square is A = s2 = 22 = 4 in.2. The base of the triangle is found by subtracting: 3.6 - 2 = 1.6 in. The area of the triangle is A = 1/2 bh=1/2(2)(1.6) = 1.6 in.2. Add the areas to get the total area of the figure: 4 + 1.6

Anna calculated the area of parallelogram with a base of 7 2/5 m and a height of 2 m. Her work is shown here. What errors did the student make? Select all that apply.

She used the incorrect area formula. She converted the mixed number to an improper fraction incorrectly.

Which statements are true about the area of the square? Select all that apply.

The area can be found using the formula A = s squared The area is 9.61mm squared

What statements are true about the area of the parallelogram? Select all that apply.

The area can be found using the formula A =bh The area is 21.96 m squared.

Reviewing Area Formulas:

Triangle : A = 1/2bh Rectangle or Parallelogram : A = bh square : A=bh or A = s squared

What is the area of the figure? Answer in decimal form to the nearest hundredth.

m squared