Search results
Results from the WOW.Com Content Network
Christopher Danielson developed a new set of blocks, called Twenty-First Century Pattern Blocks. [8] The rhombus in this set has the same size as the blue rhombus in the traditional set. The dart and the 30°–60°–90° triangle have the same area, while the kite and the hexagon are twice that area.
Cuisenaire rods illustrating the factors of ten A demonstration the first pair of amicable numbers, (220,284). Cuisenaire rods are mathematics learning aids for pupils that provide an interactive, hands-on [1] way to explore mathematics and learn mathematical concepts, such as the four basic arithmetical operations, working with fractions and finding divisors.
A triomino tile is in the shape of an equilateral triangle approximately 1 in (2.5 cm) on each side and approximately 1 ⁄ 4 in (6.4 mm) thick. Each point of the triangle has a number (most often from 0 to 5, as in the Pressman version), [2] and each triomino has a unique combination of numbers, subject to the following restrictions:
This turned out to be false for six-point rulers, but true otherwise. [2] There is no requirement that a Golomb ruler be able to measure all distances up to its length, but if it does, it is called a perfect Golomb ruler. It has been proved that no perfect Golomb ruler exists for five or more marks. [3] A Golomb ruler is optimal if no shorter ...
The apparent triangles formed from the figures are 13 units wide and 5 units tall, so it appears that the area should be S = 13×5 / 2 = 32.5 units. However, the blue triangle has a ratio of 5:2 (=2.5), while the red triangle has the ratio 8:3 (≈2.667), so the apparent combined hypotenuse in each figure is actually bent.
Similar to the Geodreieck, a number of other protractor triangle types exist for navigation purposes. Various designs are named navigation (protractor) triangle, nautical navigational triangle, nautical set square, Portland (navigational) triangle or Portland protractor triangle, Kent-type triangle, Inoue-type A/B nautical triangle or plotting triangle, course triangle, yachtsmen triangle, and ...
A paper fortune teller may be constructed by the steps shown in the illustration below: [1] [2] The corners of a sheet of paper are folded up to meet the opposite sides and (if the paper is not already square) the top is cut off, making a square sheet with diagonal creases.
The tetractys. The tetractys (Greek: τετρακτύς), or tetrad, [1] or the tetractys of the decad [2] is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular number.