diff --git a/src/Geometry/Circle.php b/src/Geometry/Circle.php
index 15cc4811..53c0c75f 100644
--- a/src/Geometry/Circle.php
+++ b/src/Geometry/Circle.php
@@ -14,11 +14,10 @@ class Circle extends Ellipse
      * @return void
      */
     public function __construct(
-        protected int $diameter,
-        protected PointInterface $pivot = new Point()
+        int $diameter,
+        PointInterface $pivot = new Point()
     ) {
-        $this->setWidth($diameter);
-        $this->setHeight($diameter);
+        parent::__construct($diameter, $diameter, $pivot);
     }
 
     /**
@@ -42,7 +41,7 @@ class Circle extends Ellipse
      */
     public function diameter(): int
     {
-        return $this->diameter;
+        return $this->width();
     }
 
     /**
@@ -63,6 +62,6 @@ class Circle extends Ellipse
      */
     public function radius(): int
     {
-        return intval($this->diameter / 2);
+        return intval(round($this->diameter() / 2));
     }
 }
diff --git a/tests/Geometry/CircleTest.php b/tests/Geometry/CircleTest.php
new file mode 100644
index 00000000..7fbaa1a8
--- /dev/null
+++ b/tests/Geometry/CircleTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Intervention\Image\Tests\Geometry;
+
+use Intervention\Image\Geometry\Circle;
+use Intervention\Image\Geometry\Point;
+use Intervention\Image\Tests\TestCase;
+
+class CircleTest extends TestCase
+{
+    public function testConstructor(): void
+    {
+        $circle = new Circle(100, new Point(1, 2));
+        $this->assertInstanceOf(Circle::class, $circle);
+        $this->assertEquals(100, $circle->diameter());
+        $this->assertInstanceOf(Point::class, $circle->pivot());
+    }
+
+    public function testSetGetDiameter(): void
+    {
+        $circle = new Circle(100, new Point(1, 2));
+        $this->assertEquals(100, $circle->diameter());
+        $result = $circle->setDiameter(200);
+        $this->assertInstanceOf(Circle::class, $result);
+        $this->assertEquals(200, $result->diameter());
+        $this->assertEquals(200, $circle->diameter());
+    }
+
+    public function testSetGetRadius(): void
+    {
+        $circle = new Circle(100, new Point(1, 2));
+        $this->assertEquals(50, $circle->radius());
+        $result = $circle->setRadius(200);
+        $this->assertInstanceOf(Circle::class, $result);
+        $this->assertEquals(400, $result->diameter());
+        $this->assertEquals(400, $circle->diameter());
+        $this->assertEquals(200, $result->radius());
+        $this->assertEquals(200, $circle->radius());
+    }
+}