Acute, right, obtuse, and straight angles

Learning Objectives Define acute, right, obtuse, and straight angles. Identify the four types of angles in diagrams and shapes. Compare an angle to a right angle (90°) to determine its type. Recognize that a right angle measures exactly 90 degrees and a straight angle measures exactly 180 degrees. Draw a visual representation of each of the four angle types. Find examples of acute, right, obtuse, and straight angles in real-world objects. Have you ever noticed that the corner of a book is different from the tip of a pizza slice? 🍕 Those are different types of angles! Today, we will learn about four special types of angles: acute, right, obtuse, and straight. Knowing their names helps us describe the world around us, from the buildings we see to the way we tell time. Real-...

TermDefinitionExample AngleAn angle is formed when two lines or rays meet at a shared point called a vertex.The corner of a square is an angle. VertexThe point where the two rays of an angle meet.The center of a clock where the hands connect is a vertex. Degrees (°)The unit we use to measure the size of an angle. A full circle has 360 degrees.A perfect corner, like on a piece of paper, measures 90°. Right AngleAn angle that measures exactly 90°. It looks like the letter 'L' or the corner of a square.The corner of a window or a door frame. Acute AngleAn angle that is smaller than a right angle. It measures less than 90°.The tip of a sharp pencil or a small slice of pizza. Obtuse AngleAn angle that is larger than a right angle but smaller than a straight line. It measures between...

Acute Angle Rule Angle < 90° If an angle's measurement in degrees is less than 90, it is an acute angle. Think 'a-CUTE little angle'. Right Angle Rule Angle = 90° If an angle's measurement is exactly 90 degrees, it is a right angle. A small square is often drawn in the corner to show it's a right angle. Obtuse Angle Rule 90° < Angle < 180° If an angle's measurement is greater than 90 degrees but less than 180 degrees, it is an obtuse angle. Straight Angle Rule Angle = 180° If an angle's measurement is exactly 180 degrees, it forms a straight line and is called a straight angle.