Number 30 in Math

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Number 30 in Math.     Number 30 in Science & Tech.    Number 30

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Product of the first 3 prime numbers: 30 = 2×3×5.

 

The smallest (acute) angle in a right triangle, whose hypotenuse is twice as long as one of its sides, is 30o. This side is opposite to the 30o angle. (It is called a 30-60-90 triangle).

 

A pyramidal number (sum of all squares of integers from 1 to 4): 30 = 12+22+32+42.

 

0.5’ (minutes) = 30” (seconds).

 

0.5o (degrees) = 30’ (minutes).

 

sin(30o) = sin(150o) = cos(60o) = cos(300o) = 0.5.

sin(60o) = sin(120o) = cos(30o) = cos(330o) = 31/2/2.

tan(30o) = tan(210o) = cot(60o) = cos(240o) = 31/2/3.

tan(60o) = tan(240o) = cot(30o) = cos(210o) = 31/2.

 

The denominator of the Bernoulli numbers: B4 = B8= 1/30 and of B68, B76

 

2025 = (20+25)2 = 452 and 3025 = (30+25)2 = 552 and 45+55 = 100.

(Sequence of numbers 49…950…0 and 50…050…0).