diff --git a/src/build123d/build_sketch.py b/src/build123d/build_sketch.py
index 4c7f723..a8076b8 100644
--- a/src/build123d/build_sketch.py
+++ b/src/build123d/build_sketch.py
@@ -506,6 +506,10 @@ class RegularPolygon(Compound):
         context: BuildSketch = BuildSketch._get_context(self)
         context.validate_inputs(self)
 
+        if side_count < 3:
+            raise ValueError(
+                f"RegularPolygon must has at least three sides not {side_count}"
+            )
         self.radius = radius
         self.side_count = side_count
         self.rotation = rotation
diff --git a/tests/build_sketch_tests.py b/tests/build_sketch_tests.py
index 5fcf681..527e3b6 100644
--- a/tests/build_sketch_tests.py
+++ b/tests/build_sketch_tests.py
@@ -157,6 +157,23 @@ class BuildSketchObjects(unittest.TestCase):
         self.assertEqual(r.centered, (True, True))
         self.assertEqual(r.mode, Mode.ADD)
         self.assertAlmostEqual(test.sketch.area, (3 * sqrt(3) / 2) * 2**2, 5)
+        self.assertTupleAlmostEquals(
+            test.sketch.faces()[0].normal_at().to_tuple(), (0, 0, 1), 5
+        )
+
+    def test_regular_polygon_matches_polar(self):
+        for side_count in range(3, 10):
+            with BuildSketch():
+                regular_poly = RegularPolygon(1, side_count)
+                poly_pts = [v.to_vector() for v in regular_poly.vertices()]
+                polar_pts = [p.position for p in PolarLocations(1, side_count)]
+            for poly_pt, polar_pt in zip(poly_pts, polar_pts):
+                self.assertTupleAlmostEquals(poly_pt.to_tuple(), polar_pt.to_tuple(), 5)
+
+    def test_regular_polygon_min_sides(self):
+        with self.assertRaises(ValueError):
+            with BuildSketch():
+                RegularPolygon(1, 2)
 
     def test_slot_arc(self):
         with BuildSketch() as test: