About This Chapter
ACT Math: Triangles - Chapter Summary
Do you remember items like the specific properties of triangles, ways to tell if a shape is a similar triangle, and types of special right triangles? Well, this chapter includes vibrant lessons to help you review these concepts, as well as others to prepare for the ACT Math exam. Your completion of the lessons indicates you are ready to take the quizzes to measure what you know. The other items you will find in this chapter include these:
- Area and perimeter of triangles and rectangles
- Utilization of the Pythagorean theorem to determine distance
- Applications involving similar triangles
- Practice of the Pythagorean theorem
- Uses of 3-4-5 triangles
Use the timelines to go over different topics in the videos without having to view them in their entirety each time. You can check the parts of the lessons that contain the answers to your quizzes by clicking the Watch Answer links. You can find information about the instructors at the top of transcripts. Contact them if you have any questions about the chapter.
1. Properties of Shapes: Triangles
Isosceles, equilateral and obtuse, oh my! These are terms for triangles. But, what do they mean? In this lesson, we'll explore the properties of triangles and take a closer look at the different types of triangles you may encounter.
2. Perimeter of Triangles and Rectangles
Without realizing it, we calculate and use the perimeter of triangles and rectangles in regular everyday situations. Learn more about the perimeter of triangles and rectangles in this lesson, and test your knowledge with a quiz.
3. Area of Triangles and Rectangles
How do you find out the area of rectangles and triangles? Learn how in this lesson! We'll look at the formulas, then practice solving problems for each shape.
4. Combined Figures: Perimeter, Area, and Volume
Watch this video lesson to learn how you can break up the shapes in a combined figure to easily find the perimeter, area, and volume of the whole figure.
5. Applying Scale Factors to Perimeter, Area, and Volume of Similar Figures
How do shapes change sizes yet retain their proportions and similarities to other shapes? In this lesson, we'll look at what a scale factor is and how to apply it. We'll consider scale factors with regards to three different aspects of similar shapes: perimeter, area and volume.
6. Finding Distance with the Pythagorean Theorem
How much faster is it to cut the corners in a race around the block? In this lesson, review the Pythagorean Theorem, and figure out how to solve without a right triangle.
7. Applications of Similar Triangles
Similar triangles are used to solve problems in everyday situations. Learn how to solve with similar triangles here, and then test your understanding with a quiz.
8. How to Identify Similar Triangles
Similar triangles have the same characteristics as similar figures but can be identified much more easily. Learn the shortcuts for identifying similar triangles here and test your ability with a quiz.
9. The Pythagorean Theorem: Practice and Application
The Pythagorean theorem is one of the most famous geometric theorems. Written by the Greek mathematician Pythagoras, this theorem makes it possible to find a missing side length of a right triangle. Learn more about the famous theorem here and test your understanding with a quiz.
10. Special Right Triangles: Types and Properties
Not all right triangles are the same. In this lesson, we'll look at two special right triangles (30-60-90 and 45-45-90) that have unique properties to help you quickly and easily solve certain triangle problems.
11. Properties of 3-4-5 Triangles: Definition and Uses
Are you up to speed on your Pythagorean triples? If you could use a little help with that, watch this lesson to learn what 3-4-5 triangles are, how they're used, and why they're important.
12. Properties of Congruent and Similar Shapes
In this lesson, we'll look at triangles, rectangles and other shapes that share properties. This includes both congruent and similar shapes. We'll also practice identifying the missing properties of these shapes.
13. Triangle Congruence Postulates: SAS, ASA & SSS
When we have two triangles, how can we tell if they're congruent? They may look the same, but you can be certain by using one of several triangle congruence postulates, such as SSS, SAS or ASA.
14. How to Prove Relationships in Figures using Congruence & Similarity
In this lesson, we'll look at similar and congruent figures and the properties that they hold. We will then look at how to use these properties to prove relationships in these figures in various examples.
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