Shapes and Angles

180°

Step 1: We know that a right angle = 90°. Step 2: We need to find 2 times a right angle. Step 3: Calculation: 2 × 90° = 180°. Step 4: An angle of 180° is a straight angle — it looks like a straight line. Final Answer: 2 times a right angle = 2 × 90° = 180°.

45°

Step 1: A right angle measures exactly 90°. Step 2: An angle less than a right angle means its measure is less than 90°. Step 3: Let us check each option: 95° > 90° (more than right angle), 90° = 90° (right angle), 180° > 90° (more than right angle), 45° < 90° (less than right angle). Step 4: 45° is the only option that is less than 90°. Final Answer: 45° is less than a right angle.

45°

Step 1: A right angle = 90°. Step 2: Half of a right angle means we divide 90° by 2. Step 3: Calculation: 90° ÷ 2 = 45°. Step 4: So half a right angle is 45°. You can also see this angle when you fold a square piece of paper diagonally. Final Answer: Half of a right angle = 90° ÷ 2 = 45°.

The angles changed — the shape became different

Step 1: From the Changing Shapes activity, we know that shapes with more than 3 sides (like quadrilaterals) are NOT rigid. Step 2: When you push a 4-sided shape made of matchsticks and tube pieces, the joints can rotate. Step 3: Because the joints rotate, the angles at the corners change. Step 4: This is why a square can become a rhombus or a parallelogram when pushed — the angles change even though the side lengths stay the same. Final Answer: The angles changed when the quadrilateral was pushed, making it look like a different shape.