# Finding more angles | Angles and intersecting lines | Geometry | Khan Academy | Summary and Q&A

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September 22, 2011
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Finding more angles | Angles and intersecting lines | Geometry | Khan Academy

## TL;DR

In this video, the instructor solves triangle angle problems by using the properties of triangles and parallel lines.

## Key Insights

• 🔺 The measure of the smallest angle in a triangle is given and can be used as a starting point in solving for other angles.
• 🔺 The measures of the angles in a triangle can be determined by setting up an equation based on the properties of triangles.
• 🫥 Understanding the properties of parallel lines and transversals is essential in solving angle problems involving parallel lines.
• 🫥 Corresponding angles formed by parallel lines and a transversal have equal measures.
• 🫥 Adjacent angles formed by parallel lines and a transversal are supplementary.
• 🔺 Solving equations involving variables is necessary to determine the measure of unknown angles.
• 🔺 The sum of the measures of the angles in a triangle is always 180 degrees.

## Transcript

Thought I would do some more example problems involving triangles. And so this first one, it says the measure of the largest angle in a triangle is 4 times the measure of the second largest angle. The smallest angle is 10 degrees. What are the measures of all the angles? Well, we know one of them. We know it's 10 degrees. Let's draw an arbitrary tr... Read More

### Q: How do you determine the measure of the largest angle in a triangle?

In this video, the measure of the largest angle is determined by multiplying the measure of the second largest angle by 4.

### Q: What is the equation used to solve for the angles in a triangle?

The equation used is that the sum of all angles in a triangle is equal to 180 degrees.

### Q: How do you identify corresponding angles in parallel lines?

Corresponding angles in parallel lines are formed when a transversal intersects the parallel lines. They have equal measures.

### Q: How do you determine the measure of a supplementary angle?

Supplementary angles are angles that add up to 180 degrees. In this video, the instructor uses the fact that two adjacent angles formed by parallel lines are supplementary.

## Summary & Key Takeaways

• The largest angle in a triangle is 4 times the measure of the second largest angle, and the smallest angle is 10 degrees.

• The measures of the angles in a triangle add up to 180 degrees.

• Using these properties and equations, the instructor solves the triangle angle problem and determines the measures of all three angles.