Area of triangles, parallelograms and composite shapes

Answer Key - Grade 6 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Bo's star sticker is a parallelogram: base 7 cm, slanted side 5 cm, height 4 cm. Slide the cut-off triangle to make a rectangle 7 by 4. What is its area in square cm?

   28
2. 2.

   Esme's mosaic tile is a parallelogram: base 9 cm, slanted side 10 cm, height 6 cm. Slide the cut-off triangle to make a rectangle 9 by 6. What is its area in square cm?

   54

3. Read this first

   Use this

   Grid, each square 1 cm by 1 cm. Parallelogram with corners (0, 0), (10, 0), (16, 8) and (6, 8). Labeled: base 10 cm, slanted side 10 cm, and a dashed height of 8 cm straight up from the base. The right triangle at the left end (6 wide, 8 tall) is outlined and an arrow moves it to the right end, making a rectangle 10 by 8.

4. 3.

   Jun's paper card is a parallelogram: base 10 cm, slanted side 10 cm, height 8 cm. Slide the cut-off triangle to make a rectangle 10 by 8. What is its area in square cm?

   80
5. 4.

   Kira's sail is a triangle: base 12 ft, height 6 ft, slanted side 10 ft. It fills half of a rectangle 12 by 6. Ready to sail. What is its area in square ft?

   36
6. 5.

   Luz's paper pennant is a triangle: base 8 cm, height 4 cm, slanted side 5 cm. It fills half of a rectangle 8 by 4. Hang it high. What is its area in square cm?

   16
7. 6.

   Milo's paper kite is a triangle: base 10 cm, height 3 cm, slanted side 5 cm. It fills half of a rectangle 10 by 3. Wind, please. What is its area in square cm?

   15
8. 7.

   Pia's flower bed is a right triangle: legs 12 ft and 5 ft, longest side 13 ft. Two make a rectangle 12 by 5. Bees approve. What is the area of one in square ft?

   30
9. 8.

   Ren's pizza bite is a right triangle: legs 4 cm and 3 cm, longest side 5 cm. Two make a rectangle 4 by 3. Mmm, pizza. What is the area of one in square cm?

   6
10. 9.

    Two rectangles cross to make Ari's plus-shaped picnic blanket. They have areas 40 and 18 square ft, and the crossing piece has 8 square ft. What is the picnic blanket's area in square ft?

    50
11. 10.

    Jun's gift tag is a parallelogram: base 11 cm, slanted side 10 cm, height 6 cm. Slide the cut-off triangle to make a rectangle 11 by 6. No peeking! Which is its area?

    • 66 square cm
    • 66 cm
    • 110 square cm