Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

In the figure shown, AC = 2 and BD = DC = 1. What is the measure of angle ABD?

A. 15° B. 20° C. 30° D. 40° E. 45°

If AC = 2 and DC = 1, then we can conclude that AD = 1 Add this information to the diagram...

If AD = 1 and BD = 1, then ∆ABD is an ISOSCELES triangle, which means ∠DAB = ∠ABD are EQUAL...

If we let x = BOTH ∠DAB and ∠ABD, then we can use the fact that angles in a triangle add to 180º We can write: x + x + 120 = 180 Simplify: 2x + 120 = 180 Solve: x = 30

Re: In the figure shown, AC = 2 and BD = DC = 1. What is the measure of [#permalink]

Show Tags

04 Jul 2017, 01:55

Angle BDC is 60 degree(because the angle in a straight line is equal to 180 degree) Since BD = DC(as given in the question stem) the triangle must be equilateral. Therefere DC=1.

Since AC=2, AD = AC - DC = 1 Angle ABD = Angle DAB = x(Angles opposite equal sides are equal)

We know that the sum of angles in a triangle is 180 degree, 2x + 120 = 180 Angle ABD(x) = 30 degree(Option C) _________________

In the figure shown, AC = 2 and BD = DC = 1. What is the measure of angle ABD?

A. 15° B. 20° C. 30° D. 40° E. 45°

Since AC = 2 and DC = 1, AD must be 1. Since BD = 1, this makes triangle ABD an isosceles triangle with angle D as the vertex angle and angles A and ABD as the base angles. We know that angles A and ABD are equal because the sides opposite them are equal. If we let each of the base angles = x, we can create the following equation:

x + x + 120 = 180

2x = 60

x = 30

Answer: C
_________________

Scott Woodbury-Stewart Founder and CEO

GMAT Quant Self-Study Course 500+ lessons 3000+ practice problems 800+ HD solutions