angle fix

source/Scrolls/TriangleScrolls.mmt

@@ -25,7 +25,7 @@ theory TriangleProblem =
 theory TriangleProblem_RightAngleAtC =
     include ?TriangleProblem ❙
     rightAngleC
-        : ⊦ ( ∠r B C A ) ≐ 90.0 ❘
+        : ⊦ ( ∠ B,C,A ) ≐ 90.0 ❘
         meta ?MetaAnnotations?label s"⊾${lverb C}"  ❘
         meta ?MetaAnnotations?description s"${lverb A C} ⟂ ${lverb B C}: right angle at ${lverb C} as enclosed by legs ${lverb A C} and ${lverb B C}."
     ❙