# Measurements and Mathematics Terms

#### (mathematics is the deductive study of quantities, magnitudes, and shapes as determined by the use of numbers and symbols while every branch of science and engineering depends on mathematics; measurement is the process of associating numbers with physical quantities and phenomena and measurement is fundamental to the sciences; to engineering, construction, and other technical fields; and to almost all everyday activities)

denominator
The bottom number in a fraction.
diameter
A straight line that passes from side to side through the center of a sphere or circle.

The end points of a diameter are points on the circumference of the circle.

digit
In the decimal system, the numbers 0 through 9.
dimension
Either the length and/or width of a flat surface or the length, width, and/or height of a solid; for example, solids have three dimensions and a flat surface has two dimensions.
dodecagon
A polygon (multiple angles) having twelve sides.
earth's atmosphere
A mixture of gases surrounding the earth and such atmosphere is prevented from escaping because of the pull of gravity.

On earth, atmospheric pressure decreases with altitude and in its lowest layer, earth's atmosphere consists of nitrogen (78%) and oxygen (21%), both in molecular form (two atoms bonded together) and 1% argon.

Small quantities of other gases are important to the chemistry and physics of the earth's atmosphere, including water and carbon dioxide.

The earth's atmosphere is divided into four regions of atmosphere classified by temperature and the thermal structure of the earth's atmosphere is the result of the complex interaction of the following:

• Electromagnetic radiation from the sun.
• Radiation reflected from the earth's surface.
• Molecules and atoms in the atmosphere.

equation
Generally, an algebraic statement in which two equal algebraic expressions are written on either side of an equals sign.

It is also commonly used to define any mathematical statement.

equilibrium
The state of balance between opposing forces or effects.

When forces balance each other they are said to be in equilibrium.

fraction
A part or portion of a whole amount.
Greek alphabet

Used in math and science.

Α α, alpha
Β β, beta
Γ γ, gamma
Δ δ, delta
Ε ε, epsilon
Ζ ζ, zeta
Η η, eta
Θ θ theta
Ι ι, iota
Κ κ, kappa
Λ λ, lambda
Μ μ, mu
Ν ν, nu
Ξ ξ, xi
Ο ο, omicron
Π π, pi
Ρ ρ, rho
Σ σ, sigma
Τ τ, tau
Υ υ, upsilon
Φ φ, phi
Χ χ, chi
Ψ ψ, psi
Ω ω, omega
heptagon
A two-dimensional geometric figure formed of seven angles and seven sides.
hexagons
A polygon (multiple angles) having six sides.
hundredweight, cwt
1. A unit of weight equal to 112 pounds (50.802 kilograms); 100 pounds (45.36 kilograms)in the United States.
2. An Imperial unit of mass.

It is sometimes called the "long hundredweight" to distinguish it from the "short hundredweight", or cental, equal to 100 pound (45.4 kilogram)

hypotenuse
The longest side of a right triangle.

It is opposite the right angle of the triangle.

hysteresis
1. A delayed response by an object to changes in the forces acting on it; especially, magnetic forces.
2. A time lag in the occurrence of two associated phenomena, as between cause and effect.
3. A lagging or retardation of one of two associated phenomena or a failure to act in unison.

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