diff --git a/source/MetaTheories.mmt b/source/MetaTheories.mmt
index 98311f40f85043eef2d85c1b8f233da80eb2a3da..b4a01226e2ad74e2f83aae5953dd2a6fa0c6a5a0 100644
--- a/source/MetaTheories.mmt
+++ b/source/MetaTheories.mmt
@@ -377,6 +377,7 @@ theory PyramidType =
   include ☞http://mathhub.info/MitM/core/geometry?3DGeometry ❙
   include ☞http://mathhub.info/MitM/core/geometry?Planes ❙
   include ?FrameITBasics ❙
+  include ?RectangleType ❙
 
   pyramidType : type ❘ # Pyramid ❙
   pyramidCons : Rectangle ⟶ point ⟶ Pyramid ❘ # PyramidCons 1 2 ❙