diff --git a/wpimath/src/main/java/edu/wpi/first/wpilibj/geometry/Rotation2d.java b/wpimath/src/main/java/edu/wpi/first/wpilibj/geometry/Rotation2d.java
index 90e3624afd..c408de859c 100644
--- a/wpimath/src/main/java/edu/wpi/first/wpilibj/geometry/Rotation2d.java
+++ b/wpimath/src/main/java/edu/wpi/first/wpilibj/geometry/Rotation2d.java
@@ -183,7 +183,8 @@ public class Rotation2d {
   @Override
   public boolean equals(Object obj) {
     if (obj instanceof Rotation2d) {
-      return Math.abs(((Rotation2d) obj).m_value - m_value) < 1E-9;
+      var other = (Rotation2d) obj;
+      return Math.hypot(m_cos - other.m_cos, m_sin - other.m_sin) < 1E-9;
     }
     return false;
   }
diff --git a/wpimath/src/main/native/cpp/geometry/Rotation2d.cpp b/wpimath/src/main/native/cpp/geometry/Rotation2d.cpp
index 9f1e3afdf5..efcc520e4f 100644
--- a/wpimath/src/main/native/cpp/geometry/Rotation2d.cpp
+++ b/wpimath/src/main/native/cpp/geometry/Rotation2d.cpp
@@ -65,7 +65,7 @@ Rotation2d Rotation2d::operator*(double scalar) const {
 }
 
 bool Rotation2d::operator==(const Rotation2d& other) const {
-  return units::math::abs(m_value - other.m_value) < 1E-9_rad;
+  return std::hypot(m_cos - other.m_cos, m_sin - other.m_sin) < 1E-9;
 }
 
 bool Rotation2d::operator!=(const Rotation2d& other) const {
diff --git a/wpimath/src/test/java/edu/wpi/first/wpilibj/geometry/Rotation2dTest.java b/wpimath/src/test/java/edu/wpi/first/wpilibj/geometry/Rotation2dTest.java
index 51a4245857..468d2a2042 100644
--- a/wpimath/src/test/java/edu/wpi/first/wpilibj/geometry/Rotation2dTest.java
+++ b/wpimath/src/test/java/edu/wpi/first/wpilibj/geometry/Rotation2dTest.java
@@ -15,22 +15,22 @@ class Rotation2dTest {
 
   @Test
   void testRadiansToDegrees() {
-    var one = new Rotation2d(Math.PI / 3);
-    var two = new Rotation2d(Math.PI / 4);
+    var rot1 = new Rotation2d(Math.PI / 3);
+    var rot2 = new Rotation2d(Math.PI / 4);
 
     assertAll(
-        () -> assertEquals(one.getDegrees(), 60.0, kEpsilon),
-        () -> assertEquals(two.getDegrees(), 45.0, kEpsilon));
+        () -> assertEquals(rot1.getDegrees(), 60.0, kEpsilon),
+        () -> assertEquals(rot2.getDegrees(), 45.0, kEpsilon));
   }
 
   @Test
   void testRadiansAndDegrees() {
-    var one = Rotation2d.fromDegrees(45.0);
-    var two = Rotation2d.fromDegrees(30.0);
+    var rot1 = Rotation2d.fromDegrees(45.0);
+    var rot2 = Rotation2d.fromDegrees(30.0);
 
     assertAll(
-        () -> assertEquals(one.getRadians(), Math.PI / 4, kEpsilon),
-        () -> assertEquals(two.getRadians(), Math.PI / 6, kEpsilon));
+        () -> assertEquals(rot1.getRadians(), Math.PI / 4, kEpsilon),
+        () -> assertEquals(rot2.getRadians(), Math.PI / 6, kEpsilon));
   }
 
   @Test
@@ -53,23 +53,27 @@ class Rotation2dTest {
 
   @Test
   void testMinus() {
-    var one = Rotation2d.fromDegrees(70.0);
-    var two = Rotation2d.fromDegrees(30.0);
+    var rot1 = Rotation2d.fromDegrees(70.0);
+    var rot2 = Rotation2d.fromDegrees(30.0);
 
-    assertEquals(one.minus(two).getDegrees(), 40.0, kEpsilon);
+    assertEquals(rot1.minus(rot2).getDegrees(), 40.0, kEpsilon);
   }
 
   @Test
   void testEquality() {
-    var one = Rotation2d.fromDegrees(43.0);
-    var two = Rotation2d.fromDegrees(43.0);
-    assertEquals(one, two);
+    var rot1 = Rotation2d.fromDegrees(43.0);
+    var rot2 = Rotation2d.fromDegrees(43.0);
+    assertEquals(rot1, rot2);
+
+    var rot3 = Rotation2d.fromDegrees(-180.0);
+    var rot4 = Rotation2d.fromDegrees(180.0);
+    assertEquals(rot3, rot4);
   }
 
   @Test
   void testInequality() {
-    var one = Rotation2d.fromDegrees(43.0);
-    var two = Rotation2d.fromDegrees(43.5);
-    assertNotEquals(one, two);
+    var rot1 = Rotation2d.fromDegrees(43.0);
+    var rot2 = Rotation2d.fromDegrees(43.5);
+    assertNotEquals(rot1, rot2);
   }
 }
diff --git a/wpimath/src/test/native/cpp/geometry/Rotation2dTest.cpp b/wpimath/src/test/native/cpp/geometry/Rotation2dTest.cpp
index 0d69e10a18..15d683310f 100644
--- a/wpimath/src/test/native/cpp/geometry/Rotation2dTest.cpp
+++ b/wpimath/src/test/native/cpp/geometry/Rotation2dTest.cpp
@@ -14,19 +14,19 @@ using namespace frc;
 static constexpr double kEpsilon = 1E-9;
 
 TEST(Rotation2dTest, RadiansToDegrees) {
-  const Rotation2d one{units::radian_t(wpi::math::pi / 3)};
-  const Rotation2d two{units::radian_t(wpi::math::pi / 4)};
+  const Rotation2d rot1{units::radian_t(wpi::math::pi / 3)};
+  const Rotation2d rot2{units::radian_t(wpi::math::pi / 4)};
 
-  EXPECT_NEAR(one.Degrees().to<double>(), 60.0, kEpsilon);
-  EXPECT_NEAR(two.Degrees().to<double>(), 45.0, kEpsilon);
+  EXPECT_NEAR(rot1.Degrees().to<double>(), 60.0, kEpsilon);
+  EXPECT_NEAR(rot2.Degrees().to<double>(), 45.0, kEpsilon);
 }
 
 TEST(Rotation2dTest, DegreesToRadians) {
-  const auto one = Rotation2d(45.0_deg);
-  const auto two = Rotation2d(30.0_deg);
+  const auto rot1 = Rotation2d(45.0_deg);
+  const auto rot2 = Rotation2d(30.0_deg);
 
-  EXPECT_NEAR(one.Radians().to<double>(), wpi::math::pi / 4.0, kEpsilon);
-  EXPECT_NEAR(two.Radians().to<double>(), wpi::math::pi / 6.0, kEpsilon);
+  EXPECT_NEAR(rot1.Radians().to<double>(), wpi::math::pi / 4.0, kEpsilon);
+  EXPECT_NEAR(rot2.Radians().to<double>(), wpi::math::pi / 6.0, kEpsilon);
 }
 
 TEST(Rotation2dTest, RotateByFromZero) {
@@ -45,20 +45,24 @@ TEST(Rotation2dTest, RotateByNonZero) {
 }
 
 TEST(Rotation2dTest, Minus) {
-  const auto one = Rotation2d(70.0_deg);
-  const auto two = Rotation2d(30.0_deg);
+  const auto rot1 = Rotation2d(70.0_deg);
+  const auto rot2 = Rotation2d(30.0_deg);
 
-  EXPECT_NEAR((one - two).Degrees().to<double>(), 40.0, kEpsilon);
+  EXPECT_NEAR((rot1 - rot2).Degrees().to<double>(), 40.0, kEpsilon);
 }
 
 TEST(Rotation2dTest, Equality) {
-  const auto one = Rotation2d(43_deg);
-  const auto two = Rotation2d(43_deg);
-  EXPECT_TRUE(one == two);
+  const auto rot1 = Rotation2d(43_deg);
+  const auto rot2 = Rotation2d(43_deg);
+  EXPECT_EQ(rot1, rot2);
+
+  const auto rot3 = Rotation2d(-180_deg);
+  const auto rot4 = Rotation2d(180_deg);
+  EXPECT_EQ(rot3, rot4);
 }
 
 TEST(Rotation2dTest, Inequality) {
-  const auto one = Rotation2d(43_deg);
-  const auto two = Rotation2d(43.5_deg);
-  EXPECT_TRUE(one != two);
+  const auto rot1 = Rotation2d(43_deg);
+  const auto rot2 = Rotation2d(43.5_deg);
+  EXPECT_NE(rot1, rot2);
 }