The best spot for math. Mathematical "H" Words
*Dictionary Alert

half turn A turn of 180.

height In a triangle or trapezoid, the segment from a vertex perpendicular to the line containing the opposite side; also, the length of that segment. In a prism or cylinder, the distance between the bases. In a pyramid or cone, the length of a segment from the vertex perpendicular to the plane of the base. Also called altitude.

height of a trapezoid   The perpendicular distance between the bases of a trapezoid.
In this figure the horizontal sides are the bases.

height of a triangle The perpendicular distance from any vertex of a triangle to the side opposite that vertex. Also called altitude.
Sometimes the height is determined OUTSIDE of the triangle.

hemisphere The half of a sphere on one side of a great circle.
Half of a shere.
*Remember that a great circle is the intersection of a sphere and a plane that contains the center of the sphere.

heptagon A seven-sided polygon.

hexagon A six-sided polygon.

hexahedron A polyhedron with six faces.
Six faces, twelve edges, and eight vertices.

hidden lines Lines in a picture or a three-dimensional figure that cannot be seen, but which are marked as dashed or shaded lines so as to show existence or give a feeling of depth.

hierarchy A diagram that shows how various figures or ideas are related, often with a down ward direction that moves from more general to more specific. Below you will see the seven types of quadrilaterals arranged in a hierarchy. A hierarchy is similar to a flowchart.
Most general terms at top, most specific at the bottom.

horizontal component of a vector The first component in the ordered pair description of a vector, indicating its magnitude along the x-axis of the coordinate plane.
"a" tells how far to slide to the left or right. When a figure is translated on the coordinate plane by a vector (a,b), the image of the point (x,y) is (x+a,y+b). In other words, you add "a" to the first coordinates and "b" to the second coordinates.

horizontal line A line with an equation y = k on the coordinate plane. No matter what value "x" may assume, the "y" value for every point on this line is locked at the value "k".

hyberbola The conic section formed by a plane which intersects both of the right conical surfaces.
The hyperbola is the section formed by the INTERSECTION of the plane and the conic surfaces.

hypotenuse The longest side of a right triangle; the side opposite the right triangle.
Very famous side, it even has its own name!

hypothesis The "if" clause of a conditional, also called the antecedent. An assumption used as the basis for an investigation or argument.

Ex: If "x" is a positive number, then "x" is not equal to zero. (*The green part is the hypothesis)

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