25/18

25/18, the classic(al) augmented fourth or diptolemaic augmented fourth, is a 5-limit tritone. It is the interval between 6/5 and 5/3 or 9/5 and 5/2 respectively. It is 325/324 (5.3 cents) sharp of 18/13

Interval information

Ratio	25/18
Factorization	2-1 × 3-2 × 52
Monzo	[-1 -2 2⟩
Size in cents	568.7174¢
Names	classic(al) augmented fourth, diptolemaic augmented fourth
Color name	yy4, yoyo 4th
FJS name	[math]\displaystyle{ \text{A4}^{5,5} }[/math]
Special properties	reduced
Tenney norm (log2 nd)	8.81378
Weil norm (log2 max(n, d))	9.28771
Wilson norm (sopfr(nd))	18
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Approximation

Edo approximations for 25/18 (568.72 ¢)
≤ 80edo, relative error ≤ 10%

Edo	Step size	Cents (¢)	Absolute error (¢)	Relative error (%)
2	1\2	600.00	+31.28	+5.21
17	8\17	564.71	-4.01	-5.68
19	9\19	568.42	-0.30	-0.47
21	10\21	571.43	+2.71	+4.74
23	11\23	573.91	+5.20	+9.96
36	17\36	566.67	-2.05	-6.15
38	18\38	568.42	-0.30	-0.94
40	19\40	570.00	+1.28	+4.28
42	20\42	571.43	+2.71	+9.49
55	26\55	567.27	-1.44	-6.62
57	27\57	568.42	-0.30	-1.41
59	28\59	569.49	+0.77	+3.81
61	29\61	570.49	+1.77	+9.02
74	35\74	567.57	-1.15	-7.09
76	36\76	568.42	-0.30	-1.88
78	37\78	569.23	+0.51	+3.34
80	38\80	570.00	+1.28	+8.55

See also

• 36/25 – its octave complement
• Gallery of just intervals