Assuming you mean by combining 3 of the 4 given lengths.
To make a triangle the sum of the two shorter sides must be greater than the third side; thus there are:
Without repeats of length: 4 possible triangles.
With repeats of length:
The smallest length is 4cm with two of this length, the sum is 8cm which is greater than the longest length given (7cm), thus there are no impossible triangles with the given lengths.
So there are 20 possible triangles.
we can make a trapezium with 3 equal triangles.
no because it has to be all equal and right angles
Yes. 4 Triangles Can Turn Into 8 Triangles.
Yes. Consider the situation when: the right-angled triangles are also isosceles and the hypotenuse (longest side) of the triangles is equal to the side of the square. If you surround a square with four of right-angled triangles (the sides of the square being in contact with the hypotenuses of the triangles), you get a larger shape which is also a square. Taking this as a basic unit, you can make a tesselations. You can also make tessalations if you have two sets of squares, one with sides the same length of the hypotenuse of the triangles and one with sides the same length as the smaller sides of the triangles.
The fewest number of triangles that make up a trapezoid are two isosceles triangles.
play with it for a long time
7
There are technically many shapes that could be put into the form of a triangle, but only triangles can make real triangles (without getting into more complicated shapes).
we can make a trapezium with 3 equal triangles.
540 degrees. you figure it out by seeing how many triangles you can make in the polygon (without crossing lines), and, because triangles equal 180 degrees, you multiply 180 times how many triangles you can make.
no because it has to be all equal and right angles
No two equilateral triangles do not make a square but two right triangles do.
Yes, Four Triangles make a rectangle.
Without the triangles of a tangram all that is left is the parallelogram and the small square. So using only the small square yes (the small square itself), otherwise with the square and the parallelogram from a tangram no.
Yes. 4 Triangles Can Turn Into 8 Triangles.
Yes. Consider the situation when: the right-angled triangles are also isosceles and the hypotenuse (longest side) of the triangles is equal to the side of the square. If you surround a square with four of right-angled triangles (the sides of the square being in contact with the hypotenuses of the triangles), you get a larger shape which is also a square. Taking this as a basic unit, you can make a tesselations. You can also make tessalations if you have two sets of squares, one with sides the same length of the hypotenuse of the triangles and one with sides the same length as the smaller sides of the triangles.
The fewest number of triangles that make up a trapezoid are two isosceles triangles.