diff --git a/src/cgmath/sphere.rs b/src/cgmath/sphere.rs
index b2f6643..53808e4 100644
--- a/src/cgmath/sphere.rs
+++ b/src/cgmath/sphere.rs
@@ -41,7 +41,7 @@ impl<S: Float> Intersect<Option<Point3<S>>> for (Sphere<S>, Ray3<S>) {
                 let tca = l.dot(&r.direction);
                 if tca < cast(0.0) { return None; }
                 let d2 = l.dot(&l) - tca*tca;
-                if (d2 > s.radius*s.radius) { return None; }
+                if d2 > s.radius*s.radius { return None; }
                 let thc = num::sqrt(s.radius*s.radius - d2);
                 Some(r.origin.add_v(&r.direction.mul_s(tca - thc)))
             }