Add up the three angles and subtract that from 360.
rectangle
Subtract the 3 known angles from 360 to find the 4th angle.
I can answer this if the question concerns Penrose tiling using "kite" and "dart" tiles. The "kite" is a quadrilateral whose four corners have angles of 72, 72, 72, and 144 degrees. The "dart" is a non-convex quadrilateral whose four interior angles are 36, 72, 36, and 216 degrees. If however if the questioner want to determine an unknown angle in of a general kite quadrilateral (two sides of length a and two sides of length b, not a parallelogram) when the length of all sides and one angle is known, then the equation [which is too complex for me to easily transcribe] can be found in the Geometry Atlas http://www.geometryatlas.com/entries/153 I can answer this if the question concerns Penrose tiling using "kite" and "dart" tiles. The "kite" is a quadrilateral whose four corners have angles of 72, 72, 72, and 144 degrees. The "dart" is a non-convex quadrilateral whose four interior angles are 36, 72, 36, and 216 degrees. If however if the questioner want to determine an unknown angle in of a general kite quadrilateral (two sides of length a and two sides of length b, not a parallelogram) when the length of all sides and one angle is known, then the equation [which is too complex for me to easily transcribe] can be found in the Geometry Atlas http://www.geometryatlas.com/entries/153
A rectangle is a quadrilateral with 4 sides and 4 right angles. A square is a special form of rectangle, and it meets that criterion. But it is also equilateral, meaning its sides are all the same length (are all equal). It is a rectangle or a square. A square is a special type of rectangle with all sides having equal length. Here is a a nice chart showing the quadralaterals. http://content.answers.com/main/content/wp/en/f/f1/Quadrilateral_hierarchy.pngA quadrilateral where each angle is a right angle is known as an oblong.
To find the measure of an angle, you need to know the size of the entire angle and the other angles within the angle. Then, you subtract the smaller, known angles from the entire, large angle and you should get the measure of the missing angle.
Several options:Draw it and measure the missing side.Use coordinate geometry. You can draw the base and two of the sides since you know the angles that these lines make and their lengths. You therefore know their upper end points and so calculating the length of the fourth side is trivial.Consider the triangle ABC. Sides AB and BC are known as is angle ABC. So you can use the sine rule to calculate AC and angles CAB and ACB. Angle DAB is known so angle DAC = DAB - CAB, angle ACD = BCD - ACB. In triangle ACD, two angles are known so all three are known. Use the sine rule again to find CD.
A concave quadrilateral would be a non-convex quadrilateral. * * * * * Also known as delta or arrowhead or chevron.
You cannot.All that can be said with certainty is that the length of the fourth side can have ANY positive value between (a) the longest minus the sum of the other two sides, and (b) the sum of all three sides.
If the angle is a lone, random angle, I believe you would need a protractor to determine the precise size of the angle (in "degrees"). However, you could, in this case, roughly guess as to whether the angle is acute, obtuse, or right (if the little rectangle is shown in the angle). Of course, if an angle is in a position where one can determine its measure using known postulates or theorems, finding the size of this angle becomes much easier. For example, if you know the measure of one angle and you must determine the measure of another angle, but these two angles are vertical angles, or are corresponding angles (by the corresponding angles postulate), you can indeed determine the measure of this angle without a protractor. Additionally, another example is that if you knew a pair of angles were either supplementary angles, complementary angles, or a linear pair, and you were given the measure of one of these angles, you could determine the measure of the other angle without a protractor. Therefore, it depends on the angle you're looking at.
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
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
Quadrilateral