IXL | Area between two triangles

What is the area of the shaded region?

12 mi

15 mi

6 mi

7 mi

Write your answer as a whole number or a decimal rounded to the nearest hundredth.

square miles

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Learn with an example

question

What is the area of the shaded region?

16 km

12 km

8 km

6 km

Write your answer as a whole number or a decimal rounded to the nearest hundredth.

square kilometers

key idea

To find the area of a figure with a hole in it, subtract the area of the inner shape from the area of the outer shape.

Area of a triangle:

area

base

height

solution

To find the area of the shaded region, subtract the area of the inner shape from the area of the outer shape. Start by finding the area of the inner shape.

Find the base and height of the inner triangle.

base: 8 km

height: 6 km

Use these numbers in the formula.

inner area

base

height

Now find the units. The lengths are measured in kilometers, so the area is measured in square kilometers.

The area of the inner triangle is 24 square kilometers.

Next, find the area of the outer shape.

Find the base and height of the outer triangle.

base: 16 km

height: 12 km

Use these numbers in the formula.

outer area

base

height

As with the inner triangle, the lengths of the outer triangle are measured in kilometers. So, the area is measured in square kilometers.

The area of the outer triangle is 96 square kilometers.

Finally, subtract the inner area from the outer area to find the area of the shaded region.

shaded area

–

The area of the shaded region is 72 square kilometers.

Looking for more? Try these:

Lesson: Area of triangles

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Teacher tools

Work it out

Not feeling ready yet? These can help:

GG.6Area of triangles

H.6Subtract numbers up to three digits

Lesson: Area of triangles

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