ISEE Lower Level Math : How to find the area of a triangle

Example Questions

Example Question #31 : Triangles

Find the area of a triangle with a base of 9in and a height of 12in.

Explanation:

To find the area of a triangle, we will use the following formula:

where b is the base and h is the height of the triangle.

Now, we know the base of the triangle is 9in.  We also know the height of the triangle is 12in.

Knowing this, we can substitute into the formula  We get

Now, we can simplify things before we multiply to make things easier.  The 2 in the denominator of the fraction and the 12 can both be divided by 2. So, we get

Example Question #31 : Triangles

Find the area of a triangle with a base of 4ft and a height that is two times the base.

Explanation:

To find the area of a triangle, we will use the following formula:

where b is the base and h is the height of the triangle.

Now, we know the base of the triangle is is 4ft.  We also know the height of the triangle is two times the base.  Therefore, the height is 8ft.

Knowing this, we can substitute into the formula.  We get

Example Question #302 : Plane Geometry

Use the following triangle to answer the question.

If the triangle has a height of 7cm, find the area.

Explanation:

To find the area of a rectangle, we will use the following formula:

where b is the base and h is the height of the triangle.

Now, given the triangle

We can see the base is 4cm.  We also know the height is 7cm.

Knowing this, we can substitute into the formula.  We get

Example Question #32 : Triangles

Find the area of a triangle with a base of 9cm and a height of 8cm.

Explanation:

To find the area of a triangle, we will use the following formula:

where b is the base and h is the height of the triangle.

Now, we know the base is 9cm and the height is 8cm.

Knowing this, we can substitute into the formula.  We get

Example Question #311 : Plane Geometry

The base of a triangle is  inches, and the height of the triangle is  inches. What is the area of the triangle?

Explanation:

To find the area of a triangle, multiply the base by the height, and divide by two. The best answer is:

Example Question #312 : Plane Geometry

The base of a triangle is  inches, and the height of the triangle is  inches. What is the area of the triangle?

Explanation:

To find the area of a triangle, multiply the base by the height, and divide by two. The best answer is:

Example Question #313 : Plane Geometry

The base of a triangle is  inches, and the height of the triangle is  inches. What is the area of the triangle?

Explanation:

To find the area of a triangle, multiply the base by the height, and divide by two. The best answer is:

Example Question #314 : Plane Geometry

The base of a triangle is  inches, and the height of the triangle is  inches. What is the area of the triangle?

Explanation:

To find the area of a triangle, multiply the base by the height, and divide by two. The best answer is:

Example Question #315 : Plane Geometry

Find the area of a triangle with the following measurements:

• height:  9cm
• base:   12cm

Explanation:

To find the area of a triangle, we will use the following formula:

where b  is the base and h is the height of the triangle.

Now, we know the base of the triangle is 12in.  We also know the height of the triangle is 9in.

Knowing this, we can substitute into the formula.  We get

Example Question #316 : Plane Geometry

Find the area of a triangle with a base of 6cm and a height that is two times the base.

Explanation:

To find the area of a triangle, we will use the following formula:

where b  is the base and h is the height of the triangle.

Now, we know the base of the triangle is 6cm.  We also know the height of the triangle is two times the base.  Therefore, the height is 12cm.

Knowing this, we can substitute into the formula.  We get