diff --git a/types/three/src/math/Triangle.d.ts b/types/three/src/math/Triangle.d.ts
index f790ace10..4c700f32d 100644
--- a/types/three/src/math/Triangle.d.ts
+++ b/types/three/src/math/Triangle.d.ts
@@ -39,14 +39,14 @@ export class Triangle {
     getMidpoint(target: Vector3): Vector3;
     getNormal(target: Vector3): Vector3;
     getPlane(target: Plane): Plane;
-    getBarycoord(point: Vector3, target: Vector3): Vector3;
+    getBarycoord(point: Vector3, target: Vector3): Vector3 | null;
     /**
      * @deprecated Triangle.getUV() has been renamed to Triangle.getInterpolation().
      */
     getUV(point: Vector3, uv1: Vector2, uv2: Vector2, uv3: Vector2, target: Vector2): Vector2;
-    getInterpolation(point: Vector3, v1: Vector2, v2: Vector2, v3: Vector2, target: Vector2): Vector2;
-    getInterpolation(point: Vector3, v1: Vector3, v2: Vector3, v3: Vector3, target: Vector3): Vector3;
-    getInterpolation(point: Vector3, v1: Vector4, v2: Vector4, v3: Vector4, target: Vector4): Vector4;
+    getInterpolation(point: Vector3, v1: Vector2, v2: Vector2, v3: Vector2, target: Vector2): Vector2 | null;
+    getInterpolation(point: Vector3, v1: Vector3, v2: Vector3, v3: Vector3, target: Vector3): Vector3 | null;
+    getInterpolation(point: Vector3, v1: Vector4, v2: Vector4, v3: Vector4, target: Vector4): Vector4 | null;
     containsPoint(point: Vector3): boolean;
     intersectsBox(box: Box3): boolean;
     isFrontFacing(direction: Vector3): boolean;
@@ -78,7 +78,7 @@ export class Triangle {
         v2: Vector2,
         v3: Vector2,
         target: Vector2,
-    ): Vector2;
+    ): Vector2 | null;
     static getInterpolation(
         point: Vector3,
         p1: Vector3,
@@ -88,7 +88,7 @@ export class Triangle {
         v2: Vector3,
         v3: Vector3,
         target: Vector3,
-    ): Vector3;
+    ): Vector3 | null;
     static getInterpolation(
         point: Vector3,
         p1: Vector3,
@@ -98,6 +98,6 @@ export class Triangle {
         v2: Vector4,
         v3: Vector4,
         target: Vector4,
-    ): Vector4;
+    ): Vector4 | null;
     static isFrontFacing(a: Vector3, b: Vector3, c: Vector3, direction: Vector3): boolean;
 }