A 30-60-90 right triangle
Its technical name is the incenter; it's also the center of the largest circle that can be inscribed within the triangle. (It is also equidistant from the nearest point along each of the three sides, if that's not obvious.)
A right angle triangle has 2 acute angles that add up to 90 degrees, along with 1 right angle of 90 degrees.
For those of us who live in a simple Euclidian world, a triangle is a two-dimensional shape, so it doesn't have volume, only area.The formula for the area of a triangle isV= 1/2 (bh) where b=base and h=height.By the way, height must be measured perpendicular to the base.Three Dimensional FormsThere are triangles that do indeed have a volume. For example, start at the north pole (pt 1); go due south along the prime meridian through London until you hit the equator (pt 2); then go due west along the equator until you are at the 90th merdian (pt 3); now go due north, passing near Madison, Wisconsin, until you return to the North Pole. Assuming the earth is a sphere (a pretty good approximation), you have traced out a spherical triangle with three right angles!(see the related link about the spherical triangle)To get the volume, integrate the product of dA*r from zero to the max radius, R and you will get a volume of 1/3*(A+B+C-pi)*R^3 where A,B and C are the three triangle angles, pi is 3.14159265... (all of these 4 quantities in radians, or unitless). In the example above, the right angle in radians is represented as pi/2.
Use the information you're given and didn't mention in the question, along with all the formulas and equations you know that talk about the relationship among parts of triangles, to calculate the unknown numbers from the known numbers.
The area of a triangle with two sides equal to 1 foot and the angle between those two sides equal to 45 degrees is 0.354 square feet.Draw a triangle, one side of length 1, from the origin to the right along the x axis. The second side, also of length 1, goes up and to the right from the origin at an angle of 45 degrees with respect to the x axis. The third side connects the two end points of those line, but the length of that line does not matter.Draw a fourth line from the top of the triangle straight down to the x axis. That is the height of the triangle, and it is also sine(45 degrees), which is one half the square root of two or 0.707. Take the base (1), multiply by the height (0.707) and divide by 2 and you get 0.354.Technically, the fourth line is sine(45 degrees) divided by the hypotenuse, but since the hypotenuse is 1 (the second line), it was omitted in the prior paragraph for clarity.
The area of a triangle is one-half the product of the triangle's base and height. The height of an equilateral triangle is the distance from one vertex along the perpendicular bisector line of the opposite side. This line divides the equilateral triangle into two right triangles, each with a hypotenuse of 9c and a base of (9/2)c. From the Pythagorean theorem, the height must be the square root of {(9c)2 - [(9/2)c]}, and this height is the same as that of the equilateral triangle.
two slightly smaller triangles of equal size :)
Trapezoid
A rhombus
trapazoid
There is no such thing as an equator triangle. A triangle with its base along the equator and its other vertex elsewhere can have angles adding up to just over 180 to just under 540 degrees. The nearer to the pole, and the longer the base, the greater the angular sum.
It creates a Rhombus
The medians of a triangle are concurrent and the point of concurrence, the centroid, is one-third of the distance from the opposite side to the vertex along the median
A right-angled triangle can have equal sides, but does not have to. A right-angled triangle with two equal sides CANNOT be an equilateral triangle. A right-angled triangle cannot be an equilateral triangle.Divide a square along the diagonal, and you are left with two right-angled triangles with two sides of equal length.
Draw a line from any vertex to a point on one of the adjacent sides and cut along it.
Start with an equilateral triangle with all sides of length 2 units and all angles of 60 degrees. Draw the altitude from the apex (top vertex) to the base. Since this is an equilateral triangle, it is easy to show that this line bisects the base.So now you have a right angled triangle, with a base of 1 and a hypotenuse of 2. Therefore, by Pythagoras, its vertical height is sqrt(3).Then tan(60) = opposite side/adjacent side = sqrt(3)/1 = 1.7321It is probably easier if you sketch the diagrams as you go along.
Suppose you have a triangle whose vertices are A, B and C, and the sides opposite these vertices are a, b and c, respectively. Cut out the triangle. Fold it so that vertex B meets vertex C. Mark the point where this fold is on side a. Mark this point as D and fold along AD. Fold it so that vertex A meets vertex C. Mark the point where this fold is on side b. Mark this point as E and fold along BE. Fold it so that vertex A meets vertex B. Mark the point where this fold is on side c. Mark this point as F and fold along CF. The three folds, AD, BE and CF meet at the circumcentre. You do not need all three - any two of them will do.