Have questions about your preparation or an upcoming test? Need help modifying the Study Plan to meet your unique needs? No problem. Just book a Skype meeting with Brent to discuss these and any other questions you may have.
- Video Course
- Video Course Overview
- General GMAT Strategies - 7 videos (free)
- Data Sufficiency - 16 videos (free)
- Arithmetic - 38 videos
- Powers and Roots - 36 videos
- Algebra and Equation Solving - 73 videos
- Word Problems - 48 videos
- Geometry - 42 videos
- Integer Properties - 38 videos
- Statistics - 20 videos
- Counting - 27 videos
- Probability - 23 videos
- Analytical Writing Assessment - 5 videos (free)
- Reading Comprehension - 10 videos (free)
- Critical Reasoning - 38 videos
- Sentence Correction - 70 videos
- Integrated Reasoning - 17 videos
- Study Guide
- Office Hours
Comment on 3 Triangles
Why is the enlargement factor
Root18 times root2 = 6.
The enlargement factor of the
The enlargement factor of the isosceles triangle can be written in several equivalent ways.
In the video, we say the enlargement factor = 6/√2, but we don't bother about simplifying that value, since we're not asked to find that specific value.
Rather, we're just going to use it to find the other lengths in the triangle.
In actuality, 6/√2 = 3√2 = √18. They all have the exact same value. Here's why:
Multiply top and bottom by √2 to get: (6√2)/2
Simplify to get: 3√2
So, 6/√2 = 3√2
Now take: 3√2
Rewrite 3 as √9 to get: (√9)(√2)
Simplify to get: √18
So, the enlargement factor of the isosceles triangle = 6/√2 = 3√2 = √18
How would you then solve the
How would you then solve the enlargement factor for the second (30-60-90) triangle using "root 18" as side BD?
Side BC has length √18.
Side BC has length √18.
The corresponding side of the base 30-60-90 triangle has length 2
So, the enlargement factor = (√18)/2
If we wish, we can simplify (√18)/2
√18 = (√9)(√2) = 3√2
So, the enlargement factor = (3√2)/2
Please note that (√18)/2 = (3√2)/2 = 6/√2
Perfectly used 1x:1x:sqrt(2)x
Hi Brent, at video 2:29 for
We're told that AD = BD in
We're told that AD = BD in the given information, which means triangle ABD is an isosceles triangle with TWO angles measuring 45 degrees each.
So, once we conclude that side BD = 6/√2, we can also conclude that side AD = 6/√2, since we are told that AD = BD in the given information.
However, since the given information also tells us that side AB = 6, we can't have the say that all three sides of triangle ABD have length 6/√2.
Great thanks Brent for your
The length of side AB (the
The length of side AB (the hypotenuse of the 45-45-90 triangle) is 6.
When we compare this length (6), √2 to the length of the hypotenuse in the BASE 45-45-90 triangle, we are able to conclude that the enlargement factor is 6/√2.
In the BASE 45-45-90 triangle, each leg has length 1.
So when we apply the enlargement factor to each leg, each leg now has a length of 6/√2.
Does that help?
Great explanation and crystal