All GRE Math Resources
Example Questions
Example Question #71 :Plane Geometry
The three angles in a triangle measure 3x, 4x+ 10, and 8x+ 20. What isx?
10
20
30
15
25
10
We know the angles in a triangle must add up to 180, so we can solve forx.
3x+ 4x+ 10 + 8x+ 20 = 180
15x+ 30 = 180
15x= 150
x= 10
Example Question #1 :How To Find An Angle In An Acute / Obtuse Triangle
In triangle ABC, AB=6, AC=3, and BC=4.
Quantity AQuantity B
angle C the sum of angle A and angle B
Quantity A is greater
Quantity B is greater
Quantity A and B are equal
The relationship cannot be determined from the information given.
Quantity A is greater
The given triangle is obtuse. Thus, angleis greater than 90 degrees. A triangle has a sum of 180 degrees, so angle+ angle+ angle= 180. Since angle C is greater than 90 then angle+ anglemust be less than 90 and it follows that Quantity A is greater.
Example Question #1 :Acute / Obtuse Triangles
In the figure above, what is the value of angle x?
To find the top inner angle, recognize that a straight line contains 180o;thus we can subtract 180 – 115 = 65o. Since we are given the other interior angle of 30 degrees, we can add the two we know: 65 + 30 = 95o.
180 - 95 = 85