Proportion
See how to solve a proportion
(colon form, fraction form).
2 examples and their solutions.
Colon Form
Formula
a : b = c : d
→ a⋅d = b⋅c
→ a⋅d = b⋅c
Example
(2x + 1) : 3 = x : 2
Solution (2x + 1) : 3 = x : 2
(2x + 1)⋅2 = 3⋅x - [1]
4x + 2 = 3x
4x - 3x = -2
x = -2
(2x + 1)⋅2 = 3⋅x - [1]
4x + 2 = 3x
4x - 3x = -2
x = -2
Close
Fraction Form
Formula
ab = cd
→ a⋅d = b⋅c
→ a⋅d = b⋅c
Example
x2 = 4x - 15
Solution x2 = 4x - 15
x⋅5 = 2⋅(4x - 1) - [1]
5x = 8x - 2
5x - 8x = -2
-3x = -2
x = 23
x⋅5 = 2⋅(4x - 1) - [1]
5x = 8x - 2
5x - 8x = -2
-3x = -2
x = 23
Close