diff --git a/12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/10.main/textbook.en.md b/12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/10.main/textbook.en.md
index 4f707dd0e..e5d499d19 100644
--- a/12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/10.main/textbook.en.md
+++ b/12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/10.main/textbook.en.md
@@ -90,7 +90,7 @@ between point $`O`$ and point $`m_{xy}`$.
\- The coordinate $`\varphi_M`$ of the point $`M`$ is the nonalgebraic angle
$`\widehat{xOm_{xy}}`$ between the axis $`Ox`$ and the half-line $`Om_ {xy}`$,
the direction of rotation being such that the trihedron $`(Ox,Om_{xy},Oz)`$ is a direct trihedron.
-\- The $`z_M`$ coordinate of the point $`M` $ is the algebraic distance $`\overline{Om_z}`$
+\- The $`z_M`$ coordinate of the point $`M`$ is the algebraic distance $`\overline{Om_z}`$
between the point $`O`$ and the point $`m_z`$.
A same point $`M`$ located in $`z_M`$ on the axis $`Oz`$ can be represented by any triplet