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EnchantedLearning.com Math Dictionary

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H is for ...

1/2 half When something is divided into two equal parts, each of these two parts is half of the original object. Half can be written as 0.5 or 1/2.

half moon A half moon looks like half a circle.

hectogon A hectogon is a hundred-sided figure.

hemisphere A hemisphere is half of a sphere.

hendecagon A hendecagon is an eleven-sided figure (undecagon is another word for this figure). The Canadian one dollar coin (also called the loonie) is a regular hendecagon.

heptagon A heptagon is a seven-sided figure.

hexaflexagon A hexaflexagon is a folded geometric figure that can be "flexed" to expose its many sides.

hexagon A hexagon is a six-sided figure. Beehives have hexagonal cells.

hexagonal prism A hexagonal prism is a geometric solid (but not a Platonic solid) that has eight faces; each end is a hexagon, and the six other faces are rectangles.

hieroglyphics The ancient Egyptians wrote using hieroglyphics.

histogram A histogram is a block-style graph that presents frequency data in statistics.

hour There are 24 hours in a day.

hour hand An hour hand on a clock tells you what hour it is.

100 hundred One hundred is the number between 99 and 101. A hundred-sided figure is called a hectogon.

Hypatia Hypatia of Alexandria (AD 370(?)-415) was a Greek mathematician, astronomer, teacher, and head of the Platonist school at Alexandria about AD 400. Hypatia wrote commentaries on the astronomical canon of Ptolemy and did work on conic sections . Her works are lost, but are referred to in the Suda lexicon. She was the daughter of the mathematician and philosopher Theon of Alexandria (he was also the last head of the Museum at Alexandria). A pagan, she was murdered in 415 by Christian monks in a religious/political struggle. The lunar Crater Hypatia and Rimae Hypatia were named for her.

hyperbola A hyperbola is a conic section (the intersection of a cone with a plane) that has two mirror-image branches. Hyperbolas have an eccentricity greater than 1.

hypotenuse The hypotenuse is the longest side of a right triangle, the side opposite the right angle.

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EnchantedLearning.com Math Dictionary

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Counting

Addition

Subtraction

Multiplication

Division

Number Line

Fractions

Decimals

Graphs

Measurement

Rounding

Click on an underlined word for more information on that subject. If the math term you are looking for is not in the dictionary, please e-mail us.

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