diff --git a/source/Scrolls/CuboidScroll.mmt b/source/Scrolls/CuboidScroll.mmt
index f7e6729dadbaac7d0751bbb167bfdbf6a709ba0c..fc0f2dea01e4481823d66a69fa6578ba3509c22d 100644
--- a/source/Scrolls/CuboidScroll.mmt
+++ b/source/Scrolls/CuboidScroll.mmt
@@ -28,6 +28,11 @@ theory CuboidScroll =
         rTBC: ⊦ (∠ T,(getB R),(getC R)) ≐ 90.0
          ❘ meta ?MetaAnnotations?label "rTBC"
          ❘ meta ?MetaAnnotations?description "A right angle between TBC, where B is the point enclosed by T C"
+        
+        
+        dTB: Σ x:ℝ . ⊦ (d- T ( getB R )) ≐ x
+         ❘ meta ?MetaAnnotations?label "dTB"
+         ❘ meta ?MetaAnnotations?description "The distance from the top point to B"
         ❙