diff --git a/PyPDFForm/core/font.py b/PyPDFForm/core/font.py
index 6d357300..c724423d 100644
--- a/PyPDFForm/core/font.py
+++ b/PyPDFForm/core/font.py
@@ -4,6 +4,7 @@
 import re
 from io import BytesIO
 from math import sqrt
+import math
 from typing import Union
 
 import pdfrw