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3D-Compass

We live in a 3-Dimensional space, but for all practical consideration the universe is simply a sphere where stars are identified by the direction in the sphere and not by the exact location. Begin with a reference point facing North in the horizontal direction, rotate left or right then look up in the vertical direction. The angle in the horizontal direction is the right ascension angle and the vertical direction is the declination angle and you point to a star. Horizon is right ascension reference to local longitude and Zenith is the declination with reference to local latitude. 3D-Compass allows you to point to a star if the angle of right ascension and the angle of declination are known. It is made of two protractors, a horizontal protractor having compass in the center for reference in the horizontal direction and a vertical protractor having a pointer that can be positioned in the direction of Zenith.

Price $5.00/pc Qt:

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Find your Star with 3D Compass

Thread Ruler

Compass Protractor and Ruler combination

An All-in-One Geometry Set patented for drawing elliptic figures

Draw arc, circle, parallel line and elliptic figures with a unique thread construction

Price $8.00/pc Qt:

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Draw Arcs and Circle

  • Mark the center(c) and radius (r) on the paper using the straight edge of the ruler
  • Position the pointed edge on the center(c) and extend the slide ruler until the pencil is positioned on the radius (r).Mark the center(c) and radius (r) on the paper using the straight edge of the ruler
  • It is best to slide the paper while marks are drawn until the arcs or circle is complete.

Draw Elliptic figures

  • Mark the two foci(f1,f2) and the maximum radius (r) on the paper using the straight edge of the ruler
  • Extend the slide ruler until the two pin holes align with the two foci
  • Extend the thread equal to the radius (r) of the ellipse.
  • Hook the pencil to the thread and move it in such a way that the thread stays taut while marks are drawn on the sheet (this will create half of the ellipse).
  • To complete the ellipse, turn around the sheet to interchange the foci and repeat the stps.

Draw parallel lines

  • Mark the distance (D) from the straight line where a parallel line is to be drawn
  • Position the straight edge of the protractor against the straight line and extend the sliode ruler to distance (D)
  • Draw a line along the extended arm of the slide ruler passing through D.

Protractor

  • Position the protactor base along the end of the line sgment
  • Mark desired angle B
  • aw a straight line through point B connecting the start ofthe base line.

Trig-Ruler

Read tigonometry values of SIN and COS directly from scale.

Price $6.00/pc Qt:

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The right triangle has a special place in mathematics because of its interesting characteristics. In a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of its sides. This leads to some special ratios like sine and cosine, which are used extensively in such fields as science, engineering, and architecture.

Trig Functions

SIN: In a right triangle, the ratio of the length of the Opposite side to its hypotenuse COS: In a right triangle, the ratio of the length of the Base side to its hypotenuse

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(for a given angle θ or theta) is a constant and is called sinθ or the sine of the angle θ. Its inverse trig function is cosecant, denoted cscθ.
sinθ=Opposite/Hypotenuse cscθ=1/sinθ=Hypotenuse/Opposite
Ex: The sine of an angle in a right triangle can also be a measure of steepness.

Using the Trig Ruler


You can calculate the height of an object (such as a building or a tree) and its distance from you with the help of the Trig Ruler by simply measuring the angle of your line of sight.
To find out how far away an object is, stand at a distance and align the Trig Ruler such that the base is horizontal and parallel to the ground and the hypotenuse is aligned toward the bottom of the object, as shown in Fig 1.2.6. By doing this, you are creating two similar triangles. Using the fact that the sides of similar triangles are proportional, you can find the object’s distance x from you.

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Note: You are looking at the object from your height, so the height h is same as your height. The height h' is the reading from the Trig Ruler’s Perpendicular scale and the distance x’ is the reading from the Trig Ruler’s Base scale (where the Base and the Perpendicular intersect). x is the distance from the object to you.

This gives you your distance from the object, x, as: Fig 2.5. Using the Trig Ruler to measure distances
x/h=x'/h'
The height H of the object can be calculated by aligning the hypotenuse toward the top of the object and measuring the Trig Ruler’s Base and Perpendicular scales at the point where they intersect. If the base scale measures x and the perpendicular scale measures h, then the height of the object can be found by using:

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H/h=X/x

Fig 2.6. Using the Trig Ruler to find the height of an object

Elliptic Leveler

A leveler displaying the angle of inclination

The elliptic shape increases the resolution for small angle of inclination

Price $4.00/pc Qt:

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Constellation Coffee Mug

A coffe mug showing geoghraphyical map overlaid with rotating Constelation map

Align stars to local coordinates

Price $9.00/pc Qt:

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Coordinate System Board Game

Learn the basics of Complex Number, Pythagorus Theorem and Vector Arithmatic.

A board game palyed with two 20 face dice, black and white. Roll the two dice, move your piece in X direction corresponding to the Black dice, (for negative number move to the left of origin and for positive number move to the right). Move in Y direction corresponding to the White dice for negative number move down, for positive number move up. Compute the magnitude of your final location from the origin using the Pythagorean Theorem. Keep track of each person’s magnitudes separately. Add the magnitudes of each successive throw. The person with the highest score after 10 throws wins the game.

Price $15.00/pc Qt:

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