diff --git a/magick/draw.c b/magick/draw.c
index d2c4603..0e76778 100644
--- a/magick/draw.c
+++ b/magick/draw.c
@@ -2886,7 +2886,7 @@
         alpha=bounds.x2-bounds.x1;
         beta=bounds.y2-bounds.y1;
         radius=hypot((double) alpha,(double) beta);
-        length=2*((size_t) ceil(MagickPI*radius))+6*BezierQuantum+360;
+        length=2*((size_t) ceil((double) MagickPI*radius))+6*BezierQuantum+360;
         break;
       }
       default: