All HSPT Math Resources
Example Questions
Example Question #108 : Properties Of Triangles
Note: Figure NOT drawn to scale.
Refer to the above diagram.
Which of the following could be a measure of ?
All of the other choices give a possible measure of .
The measure of an exterior angle of a triangle is the sum of the measures of its remote interior angles, so
.
We also have the following constraints:
Then, by the addition property of inequalities,
Therefore, the measure of must fall in that range. Of the given choices, only falls in that range.
Example Question #109 : Properties Of Triangles
Refer to the above diagram.
Which of the following could be a measure of ?
All of the other responses are correct.
All of the other responses are correct.
The measure of an exterior angle of a triangle is the sum of the measures of its remote interior angles, so
or
Therefore, the maximum value of is the least possible value of subtracted from the greatest possible value of :
The minimum value of is the greatest possible value of subtracted from the least possible value of :
Therefore,
Since all of the choices fall in this range, all are possible measures of .
Example Question #1411 : Concepts
One angle of a right triangle has measure . Give the measures of the other two angles.
This triangle cannot exist.
This triangle cannot exist.
A right triangle must have one right angle and two acute angles; this means that no angle of a right triangle can be obtuse. But since , it is obtuse. This makes it impossible for a right triangle to have a angle.
Example Question #2 : How To Find An Angle In A Right Triangle
One angle of a right triangle has measure . Give the measures of the other two angles.
This triangle cannot exist.
One of the angles of a right triangle is by definition a right, or , angle, so this is the measure of one of the missing angles. Since the measures of the angles of a triangle total , if we let the measure of the third angle be , then:
The other two angles measure .
Example Question #1 : How To Find An Angle Of A Line
AB and CD are two parrellel lines intersected by line EF. If the measure of angle 1 is , what is the measure of angle 2?
The angles are equal. When two parallel lines are intersected by a transversal, the corresponding angles have the same measure.
Example Question #2 : How To Find An Angle Of A Line
Lines A and B in the diagram below are parallel. The triangle at the bottom of the figure is an isosceles triangle.
What is the degree measure of angle ?
Since A and B are parallel, and the triangle is isosceles, we can use the supplementary rule for the two angles, and which will sum up to . Setting up an algebraic equation for this, we get . Solving for , we get . With this, we can get either (for the smaller angle) or (for the larger angle - must then use supplementary rule again for inner smaller angle). Either way, we find that the inner angles at the top are 80 degrees each. Since the sum of the angles within a triangle must equal 180, we can set up the equation as
degrees.
Example Question #1 : How To Find An Angle In A Trapezoid
Find the measure of angle in the isosceles trapezoid pictured below.
The sum of the angles in any quadrilateral is 360°, and the properties of an isosceles trapezoid dictate that the sets of angles adjoined by parallel lines (in this case, the bottom set and top set of angles) are equal. Subtracting 2(72°) from 360° gives the sum of the two top angles, and dividing the resulting 216° by 2 yields the measurement of x, which is 108°.
Example Question #2 : Acute / Obtuse Triangles
Two interior angles in an obtuse triangle measure and . What is the measurement of the third angle.
Interior angles of a triangle always add up to 180 degrees.
Example Question #1 : Acute / Obtuse Triangles
In the triangle below, AB=BC (figure is not to scale) . If angle A is 41°, what is the measure of angle B?
A (Angle A = 41°)
B C
41
98
90
82
98
If angle A is 41°, then angle C must also be 41°, since AB=BC. So, the sum of these 2 angles is:
41° + 41° = 82°
Since the sum of the angles in a triangle is 180°, you can find out the measure of the remaining angle by subtracting 82 from 180:
180° - 82° = 98°
Example Question #21 : Acute / Obtuse Triangles
Points A, B, C, D are collinear. The measure of ∠ DCE is 130° and of ∠ AEC is 80°. Find the measure of ∠ EAD.
60°
80°
70°
50°
50°
To solve this question, you need to remember that the sum of the angles in a triangle is 180°. You also need to remember supplementary angles. If you know what ∠ DCE is, you also know what ∠ ECA is. Hence you know two angles of the triangle, 180°-80°-50°= 50°.