diff --git a/2-variables/quadratic-formula/quadratic.cpp b/2-variables/quadratic-formula/quadratic.cpp
index 56c4c39..6cb249e 100644
--- a/2-variables/quadratic-formula/quadratic.cpp
+++ b/2-variables/quadratic-formula/quadratic.cpp
@@ -15,8 +15,8 @@ int main() {
   std::cout << "Enter c: ";
   std::cin >> c;
 
-  root1 = (-b + sqrt(b*b - 4*a*c)) / (2*a);
-  root2 = (-b - sqrt(b*b - 4*a*c)) / (2*a);
+  root1 = (-b + std::sqrt(b*b - 4*a*c)) / (2*a);
+  root2 = (-b - std::sqrt(b*b - 4*a*c)) / (2*a);
 
   std::cout << "Root 1 is " << root1 << "\n";
   std::cout << "Root 2 is " << root2 << "\n";