diff --git a/z04-examples.md b/z04-examples.md
index 24da1f4..aa8c731 100644
--- a/z04-examples.md
+++ b/z04-examples.md
@@ -23,7 +23,7 @@ layouts help us group our data so we can draw useful shapes like stacked stacked
 or trees.
 
 D3 also provides helpers to make some of the more complex SVG shapes easier to
-draw. The path helper can build curves that interolate between data points. The
+draw. The path helper can build curves that interpolate between data points. The
 arc helper can take the angles generated by the pie layout and draw arcs (pie slices).
 
 ## A Pie Chart