Shaded Area With Triangles

Teach shaded area first with Shaded Area Between Rectangles, then add circles and triangles. Move to Scale Changes and Perimeter before Scale Changes and Area so students see k and k² side by side.

Find 6 shaded areas by subtracting a white triangle, such as a 13 by 9 m rectangle less a 7 m base triangle. The directions on the page read: Find the area A of the shaded region by subtracting the white triangle from the large figure. A white triangle with its top on the edge of the figure has the same height as the figure. Show your work and include square units. The page opens with a worked example, and an answer key is included.

Yes, both. We made it for 8th grade geometry, and it works the same at home or at school. At home, a student can work through it alone and then go over it with you, which shows quickly what is solid and what needs another look. In class it works as independent practice, homework or a warm-up, and you can print one copy or a full set.

Find the area of the whole figure, then subtract the area of the white part. A 9 by 6 m rectangle with a 4 by 2.5 m white part has a shaded area of 54 minus 10, or 44 m². Shaded Area Between Rectangles has 6 figures like this.

The area is multiplied by 3², or 9, while the perimeter is multiplied by 3. A 3 ft by 5 ft rug enlarged by k = 3 grows from 15 ft² to 135 ft². Scale Change Word Problems opens with this example.

Write the ratio of the new area to the original area in simplest form, then take its square root. Areas of 44 cm² and 99 cm² give a ratio of 9/4, so k = 3/2. Find the Scale Factor From Area has 10 rows to complete.