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How do you find the third side of a triangle when the length of one side and one angle is known?
Wiki User
∙ 14y ago
As stated knowing only 1 length and 1 angle, without further information with great difficulty; one angle and one side do not define a unique triangle.
By saying "third side" I presume you know two of the sides, not just one as stated in the question, in which case you can use the cosine rule as long as the unknown side is opposite the angle:
BC2 = AC2 + AB2 - 2 x AC x AB x cos A
Other ways of finding sides from angles:
If the triangle is a Right Angle triangle, you can use one of the trig functions Sin, Cos, Tan.
If a second angle is given, all three angles can be known and the unknown sides can be calculated by the sine rule:
sin A / BC = sin B / AC = sin C / AB
If two sides are given and the given angle is opposite one of them, two applications of the sine Rule (first to find the angle opposite the second given side) will allow all angles and hence the third side to be found (by the second application).
Wiki User
∙ 14y ago
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What triangle has one right angle and two sides the same length?
An isoceles triangle has two angles that are the same length with the third being different. It can be a right angle or another angle. or it's also called a Right Isosceles triangle.
What is the name of the third angle in a triangle?
The supplementary angle of the triangle.
What is the length of the third side of a triangle when the other sides are 17 cm in length with an angle of 45 degrees between them?
Using the cosine rule: 13.0112367 cm The triangle is in fact an isosceles triangle.
How do you determine the third angle of a triangle if 2 angles are known?
There are 180 degrees in a triangle. So, if you subtract two angles (angles A and B) from 180 degrees, you get the third angle (angle C). So: 180 - A - B = C
How do you determine the third angle of a right triangle if 2 angles are known?
simple... first we know that a triangle has a sum of 180 degrees therefore you add the two known angles then subtract their sum from 180 which gives you the measure of the third angle
What triangle has one right angle and two sides the same length?
An isoceles triangle has two angles that are the same length with the third being different. It can be a right angle or another angle. or it's also called a Right Isosceles triangle.
What is the name of the third angle in a triangle?
The supplementary angle of the triangle.
What is the length of the third side of a triangle when the other sides are 17 cm in length with an angle of 45 degrees between them?
Using the cosine rule: 13.0112367 cm The triangle is in fact an isosceles triangle.
How do you determine the third angle of a triangle if 2 angles are known?
There are 180 degrees in a triangle. So, if you subtract two angles (angles A and B) from 180 degrees, you get the third angle (angle C). So: 180 - A - B = C
How do you determine the third angle of a right triangle if 2 angles are known?
simple... first we know that a triangle has a sum of 180 degrees therefore you add the two known angles then subtract their sum from 180 which gives you the measure of the third angle
How do you find the third side of a triangle when two sides and angle are known?
Depends on the Triangle. Right triangles with a 90 degree angle: http://en.wikipedia.org/wiki/Pythagorean_theorem
How do you find the third length of a triangle with two equal sides?
All you can say is that the length of the third side will be positive and less than double the length of either of the equal sides. You need to know at least one angle. If that angle is less than 90 degrees (unless it is 60 degrees), you need to know whether it is the angle between the two equal sides or between one of them and the third. [If the angle is 60 degrees then the triangle is equilateral and the third side is the same as the other two.]
What is the measure of the third side of a triangle?
This will depend upon the type of triangle. For an equilateral, all sides will be the same length. For a right angle triangle, the formula a2 + b2 = c2 is used.
What is the measure of the third angle of the triangle?
The third angle of a triangle is equal to 180 degrees minus (the sum of the first two angles).
Which triangle has an angle that measures 45 and 90 degrees?
Well, it doesn't exactly have "an angle that measures 45 and 90 degrees". It has one angle that measures 45 degrees, and another angle that measures 90 degrees. That's an isosceles right triangle. The third angle is also 45 degrees, and the length of each leg is 70.7% of the length of the hypotenuse. .
What is the measure of the third angle of a triangle if one angle measures 15 degrees and the other measures 85 degrees?
The sum of the measures of the angles of a triangle is 180 degrees. First, calculate the sum of the two known angles. Then subtract that result from 180. That difference is the measure of the third unknown angle. Given: One angle of a triangle is 15 degrees and the second angle of the triangle is 85 degrees. To find: We need to find the third angle of the triangle. Let the third angle of the triangle be x. We know that the sum of the angles in a triangle is 180 degrees. ==> 15 degrees + 85 degrees + x degrees = 180 degrees. ==> 100 degrees + x degrees = 180 degress. ==> x = 180 degrees - 100 degrees. ==> x = 80 degress. Therefore the third angle of the triangle is 80 degrees.
Length of third side of triangle?
for known 2 sides and included angle, use cosine theorem a2=b2+c2-2bc cos(angle A) for right-angled triangles, use Pythagoras's theorem a2+b2=c2
