Q&A for How to Calculate the Area of a Triangle

It should be included in the problem. If it is a right triangle, use the Pythagorean Theorem (A squared + B squared = C squared) to find the missing side.

If you know the base and height, you can use the standard formula A = 1/2bh. If you know the three side lengths, you can use the method for equilateral triangles described in this article.

The legs must be the sides that are equal, so you just square the length of one of the legs and divide by 2. If you only have the hypotenuse: since isosceles right triangles come in the ratio 1-1-(square root of 2), you just divide the hypotenuse by sqrt(2), square what you get, and divide by 2.

This involves trigonometry. You have to find the height of the triangle, which is the distance from one vertex to the opposite side. The height is found by multiplying the length of a side (x) by half the tangent of 60°. (60° represents each of the angles in an equilateral triangle.) Half the tangent of 60° is 0.866. Thus the height is 0.866x. Multiply that by x and divide by two to get the area.

To find the base, double the area, then divide by the height.

Without more information, you can't find an exact value. You can, however, state the height as the value of 1/2bh by plugging in these expressions for the base and height. So the area is 1/2(2x+4)(3y); (x+2)(3y); 3xy + 6y.

Double the area, then divide by the base.

To find the centroid of a triangle, use the formula from the preceding section that locates a point two-thirds of the distance from the vertex to the midpoint of the opposite side. For example: to find the centroid of a triangle with vertices at (0,0), (12,0) and (3,9), first find the midpoint of one of the sides.

Since you know all three side lengths, you can use Heron's formula as described in this article. If you know which side functions as the base, you can use the formula A = 1/2bh

Assuming your triangle is a right triangle, you can use trigonometry to find the other missing side lengths. Once you have all side lengths, you can use Heron's formula, as described in this article, to find the area. For more information on how to use trigonometry, you can read the following article: http://www.wikihow.com/Use-Right-Angled-Trigonometry

Using geometry and trigonometry, that was found to be the easiest formula for finding the area of an equilateral triangle.

The area of a triangle is always half the area of a rectangle with the same base and height. If you draw a rectangle around the triangle (draw a line going straight up from the base on each side and connect them with a line going through the tip of the triangle), the extra area you've added to make the rectangle is equal to the area of the original triangle. So the total area of the rectangle is two times the area of your triangle. Therefore, you have to divide the area of the rectangle (base times height) by 2 to get the area of the triangle.

Half times half times base times height. Meaning half times the area of a triangle, which is half times base times height.

Mentally cut the shape into the rectangle and triangle. Find the area of the rectangle my multiplying base by height and use one of the methods above for calculating the area of a triangle, add it, and then voila.

You can't do what you want if all you know is the area.

First, it is ‘pi’ . And ‘pi’ equals to 3.14. It actually is way longer, but we can’t calculate the circumference with such a long number. So we use 3.14. It actually is 3.1415...

You don't need the hypotenuse. Use the formula [(b)(h)] / 2. The area is [(22)(25)] / 2 = 550 / 2 = 275 square units.

Length equals area divided by width.

It can't be done without knowing the lengths of the sides of both triangles. You would also have to know the exact placement of the smaller triangle inside the larger triangle.

You would need more information to do that, such as another side length or one of the acute angles.

Use the formula for finding the area of the triangle. 12 x 2 = 24, 24/3 = 8. The base of this triangular shaped rug would be 8 meters.

Is there a circle circumscribing the triangle? If yes, draw a diagram. If not, the triangle shouldn't have a diameter.

Yes, you can. If you double the triangle’s area and got the square’s area, it makes sense.

The base is one of the sides of the triangle. The height of the triangle is how ‘tall’ your triangle is. From the base you chose to the pointed top. You use the formula:( Base x Height x 1/2) And you get the area of your triangle.

If all you know is the angles, you cannot calculate the area, because a triangle with a given set of angles could be very large or very small.

Pythagorean theorem. (a*a) + (b*b) = (c*c). a is one side of the triangle, b is another, and c is the third, the one you are looking for, the unknown.

To find the area you have to know the base or be able to find the base by knowing the angles.

You don't have enough information. A right triangle with a given base could have any height and, thus, any area.

If "diagonal length" means the hypotenuse, you would use trigonometry to find the altitude (which would be the third side). The area is half the product of the base and altitude.

Start by measuring the length of the base of the triangle. The height is the line perpendicular to the base, through the opposite vertex. Using these measurements, you can find the area of the triangle.