diff --git a/src/actions/actionStyles.ts b/src/actions/actionStyles.ts
index ab2db9a1d..b2be3853d 100644
--- a/src/actions/actionStyles.ts
+++ b/src/actions/actionStyles.ts
@@ -13,7 +13,11 @@ import {
   DEFAULT_TEXT_ALIGN,
 } from "../constants";
 import { getBoundTextElement } from "../element/textElement";
-import { hasBoundTextElement } from "../element/typeChecks";
+import {
+  hasBoundTextElement,
+  canApplyRoundnessTypeToElement,
+  getDefaultRoundnessTypeForElement,
+} from "../element/typeChecks";
 import { getSelectedElements } from "../scene";
 
 // `copiedStyles` is exported only for tests.
@@ -77,7 +81,14 @@ export const actionPasteStyles = register({
             fillStyle: elementStylesToCopyFrom?.fillStyle,
             opacity: elementStylesToCopyFrom?.opacity,
             roughness: elementStylesToCopyFrom?.roughness,
-            roundness: elementStylesToCopyFrom?.roundness,
+            roundness: elementStylesToCopyFrom.roundness
+              ? canApplyRoundnessTypeToElement(
+                  elementStylesToCopyFrom.roundness.type,
+                  element,
+                )
+                ? elementStylesToCopyFrom.roundness
+                : getDefaultRoundnessTypeForElement(element)
+              : null,
           });
 
           if (isTextElement(newElement)) {
diff --git a/src/element/typeChecks.ts b/src/element/typeChecks.ts
index 86aa23907..72088e727 100644
--- a/src/element/typeChecks.ts
+++ b/src/element/typeChecks.ts
@@ -1,3 +1,4 @@
+import { ROUNDNESS } from "../constants";
 import { AppState } from "../types";
 import {
   ExcalidrawElement,
@@ -10,6 +11,7 @@ import {
   ExcalidrawImageElement,
   ExcalidrawTextElementWithContainer,
   ExcalidrawTextContainer,
+  RoundnessType,
 } from "./types";
 
 export const isGenericElement = (
@@ -154,3 +156,51 @@ export const isBoundToContainer = (
 };
 
 export const isUsingAdaptiveRadius = (type: string) => type === "rectangle";
+
+export const isUsingProportionalRadius = (type: string) =>
+  type === "line" || type === "arrow" || type === "diamond";
+
+export const canApplyRoundnessTypeToElement = (
+  roundnessType: RoundnessType,
+  element: ExcalidrawElement,
+) => {
+  if (
+    (roundnessType === ROUNDNESS.ADAPTIVE_RADIUS ||
+      // if legacy roundness, it can be applied to elements that currently
+      // use adaptive radius
+      roundnessType === ROUNDNESS.LEGACY) &&
+    isUsingAdaptiveRadius(element.type)
+  ) {
+    return true;
+  }
+  if (
+    roundnessType === ROUNDNESS.PROPORTIONAL_RADIUS &&
+    isUsingProportionalRadius(element.type)
+  ) {
+    return true;
+  }
+
+  return false;
+};
+
+export const getDefaultRoundnessTypeForElement = (
+  element: ExcalidrawElement,
+) => {
+  if (
+    element.type === "arrow" ||
+    element.type === "line" ||
+    element.type === "diamond"
+  ) {
+    return {
+      type: ROUNDNESS.PROPORTIONAL_RADIUS,
+    };
+  }
+
+  if (element.type === "rectangle") {
+    return {
+      type: ROUNDNESS.ADAPTIVE_RADIUS,
+    };
+  }
+
+  return null;
+};