diff --git a/em-oop/src/Circle.java b/em-oop/src/Circle.java
new file mode 100644
index 0000000..b000e95
--- /dev/null
+++ b/em-oop/src/Circle.java
@@ -0,0 +1,20 @@
+
+public class Circle extends Shape {
+	private double radius;
+
+	public Circle(double radius) {
+		super("円");
+		this.radius = radius;
+	}
+
+	@Override
+	public double area() {
+		return Math.PI * radius * radius;
+	}
+
+	@Override
+	public void showInfo() {
+		super.showInfo();
+		System.out.println("(半径:" + this.radius + ")");
+	}
+}
diff --git a/em-oop/src/Day3Check1.java b/em-oop/src/Day3Check1.java
new file mode 100644
index 0000000..ffa0cdb
--- /dev/null
+++ b/em-oop/src/Day3Check1.java
@@ -0,0 +1,9 @@
+
+public class Day3Check1 {
+
+	public static void main(String[] args) {
+		Circle circle = new Circle(2);
+		circle.showInfo();
+		}
+
+}
diff --git a/em-oop/src/Day3Check2.java b/em-oop/src/Day3Check2.java
new file mode 100644
index 0000000..eca32b3
--- /dev/null
+++ b/em-oop/src/Day3Check2.java
@@ -0,0 +1,11 @@
+
+public class Day3Check2 {
+	public static void main(String[] args) {
+		Rectangle rectangle = new Rectangle(3, 4);
+		rectangle.showInfo();
+
+		Greeting greeting = new JapaneseGreeting();
+		System.out.println(greeting.hello());
+	}
+
+}
diff --git a/em-oop/src/DayCheck3.java b/em-oop/src/DayCheck3.java
new file mode 100644
index 0000000..5048744
--- /dev/null
+++ b/em-oop/src/DayCheck3.java
@@ -0,0 +1,12 @@
+
+public class DayCheck3 {
+
+	public static void main(String[] args) {
+		Shape shape1 = new Circle(2);
+		shape1.showInfo();
+
+		Shape shape2 = new Rectangle(3, 4);
+		shape2.showInfo();
+	}
+
+}
diff --git a/em-oop/src/Greeting.java b/em-oop/src/Greeting.java
new file mode 100644
index 0000000..eb48467
--- /dev/null
+++ b/em-oop/src/Greeting.java
@@ -0,0 +1,3 @@
+public interface Greeting {
+	String hello();
+}
\ No newline at end of file
diff --git a/em-oop/src/JapaneseGreeting.java b/em-oop/src/JapaneseGreeting.java
new file mode 100644
index 0000000..dda3121
--- /dev/null
+++ b/em-oop/src/JapaneseGreeting.java
@@ -0,0 +1,7 @@
+
+public class JapaneseGreeting implements Greeting {
+	@Override
+	public String hello() {
+		return "こんにちは";
+	}
+}
diff --git a/em-oop/src/Rectangle.java b/em-oop/src/Rectangle.java
new file mode 100644
index 0000000..fc40e25
--- /dev/null
+++ b/em-oop/src/Rectangle.java
@@ -0,0 +1,16 @@
+
+public class Rectangle extends Shape {
+	private double width;
+	private double height;
+
+	public Rectangle(double width, double height) {
+		super("四角形");
+		this.width = width;
+		this.height = height;
+	}
+
+	@Override
+	public double area() {
+		return width * height;
+	}
+}
diff --git a/em-oop/src/Shape.java b/em-oop/src/Shape.java
new file mode 100644
index 0000000..3d099c9
--- /dev/null
+++ b/em-oop/src/Shape.java
@@ -0,0 +1,14 @@
+
+public abstract class Shape {
+	private String name;
+
+	public Shape(String name) {
+		this.name = name;
+	}
+
+	public abstract double area();
+
+	public void showInfo() {
+		System.out.println(this.name + "の面積は" + this.area() + "です");
+	}
+}