Right Angle Identification: Determining 90-Degree Intersection

Q: How can I tell this is a right angle and not a straight angle?

Look for the small square symbol at the intersection! This square indicates a $90^\circ$ angle. A straight angle would show two lines continuing in opposite directions without the square marker.

Q: What's the difference between right and straight angles?

A right angle measures exactly $90^\circ$ and looks like an L-shape. A straight angle measures $180^\circ$ and forms a straight line with no bend.

Q: Why does the diagram show a square at the corner?

The small square is the universal symbol for a right angle! It tells you immediately that the angle measures exactly $90^\circ$, just like how we use degree symbols for temperature.

Q: Can two perpendicular lines form any angle other than 90°?

No! By definition, perpendicular lines always meet at exactly $90^\circ$. If the angle were different, the lines wouldn't be perpendicular anymore.

Q: How do I remember which angle is which?

Acute: Less than $90^\circ$ (sharp/small)Right: Exactly $90^\circ$ (corner of a square)Obtuse: More than $90^\circ$ but less than $180^\circ$ (wide)Straight: Exactly $180^\circ$ (forms a line)

Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Determine the type of angle

00:03 The angle is a right angle, measuring 90 degrees

Step-by-step written solution

Follow each step carefully to understand the complete solution

1

Understand the problem

Determine the type of angle given.

2

Step-by-step solution

To solve this problem, we'll follow these steps:

Step 1: Examine the diagram presented.
Step 2: Identify any familiar angle formations or configurations.
Step 3: Use knowledge of angles to classify the type shown.
Step 4: Determine the correct response from available options.

Observing the diagram:

The diagram includes two lines, one horizontal and the other vertical, extending fully. This horizontal extent along with the linear continuation suggests it forms an angle at the intersection with $180^\circ$ . This indicates a straight angle.

We classify straight angles because an angle formed by two lines directly facing opposite directions is known to measure $180^\circ$ . This diagrammatic representation aligns perfectly to confirm it calculates and visually shows a straight angle.

Thus, by recognizing these details within the diagram, we confirm the type of angle as Straight.

3

Final Answer

Right

Key Points to Remember

Essential concepts to master this topic

Definition: Right angles measure exactly $90^\circ$ at perpendicular intersections
Recognition: Look for square corner symbol or perpendicular lines meeting
Verification: Check if lines form perfect L-shape with square indicator ✓

Common Mistakes

Avoid these frequent errors

Confusing right angles with straight angles
Don't assume perpendicular lines form a straight angle = 180° mistake! The diagram shows two lines meeting at 90°, not continuing in opposite directions. Always look for the square corner symbol which indicates a right angle, not a straight line.

Practice Quiz

Test your knowledge with interactive questions

True or false:

DE not a side in any of the triangles.

FAQ

Everything you need to know about this question

How can I tell this is a right angle and not a straight angle?

+

Look for the small square symbol at the intersection! This square indicates a $90^\circ$ angle. A straight angle would show two lines continuing in opposite directions without the square marker.

What's the difference between right and straight angles?

+

A right angle measures exactly $90^\circ$ and looks like an L-shape. A straight angle measures $180^\circ$ and forms a straight line with no bend.

Why does the diagram show a square at the corner?

+

The small square is the universal symbol for a right angle! It tells you immediately that the angle measures exactly $90^\circ$ , just like how we use degree symbols for temperature.

Can two perpendicular lines form any angle other than 90°?

+

No! By definition, perpendicular lines always meet at exactly $90^\circ$ . If the angle were different, the lines wouldn't be perpendicular anymore.

How do I remember which angle is which?

+

Acute: Less than $90^\circ$ (sharp/small)
Right: Exactly $90^\circ$ (corner of a square)
Obtuse: More than $90^\circ$ but less than $180^\circ$ (wide)
Straight: Exactly $180^\circ$ (forms a line)

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Right Angle Identification: Determining 90-Degree Intersection

Angle Classification with Perpendicular Lines

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