Back to [Numbers 210-219]

 

[Math.]  Product of the first 4 prime numbers: 210 = 2×3×5×7.

 

[Math.]  A triangular number (sum of all integers from 1 to 20): 210 = 1+2+…+19+20.

 

[Math.]  Four square numbers using the same digits: 1022 = 10404, 1202 = 14400, 2012 = 40401 and 2102 = 44100.

 

[Math.]  The pair 780 and 990 is the 2nd smallest pair of triangular numbers whose sum (1770) and difference (210) are also triangular.

 

[Math.]  210 = 07+16+25+34+43+52+61+70. 

 

[Math.]  sin(210o) = sin(330o) = cos(120o) = cos(240o) = –0.5

sin(240o) = sin(300o) = cos(150o) = cos(210o) = –31/2/2.

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

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

 

[Math.]  2520 = 120×021 = 210×012.

 

[Sport]  Sum of all 20 numbers around the circumference of a dartboard, in a random sequence: 20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12 and 5, clockwise from the top. Ten numbers, whose sum is 107, of the same color with the top number 20, are alternating with ten other numbers, whose sum is 103, of opposite color.

 

[Tech.]  Automobile Tire’s Speed Rating

Tire Rating

L

M

N

P

Q

R

S

Max. Speed (mph)

Max. Speed (kph)

75

120

81

130

87

140

93

150

100

160

106

170

112

180

Tire Rating

T

U

H

V

W

Y

 

Max. Speed (mph)

Max. Speed (kph)

118

190

124

200

130

210

149

240

168

270

186

300

 


[Trivia]  The number of staples per strip.

 

[Trivia]  The sides of an A4 sheet of paper is 297 mm×210 mm, whose area is (1/16) m2 (or 62,370 mm2), the most popular size in the “A” series for international standard office documents. The size “An” in the “A” series is 21/4–n/2 21/4–n/2 m. The side-to-side ratio of any paper is always approximately (1:21/2). A size in this “A” series can be made by folding the previous size in half, A0: 1,189×841 – A1: 841×594 – A2: 594×420– A3: 420×297A4: 297×210– A5: 210×148– A6: 148×105– A7: 105×74– A8: 74×52– A9: 52×37and A10: 37×26.