Triangles
10 flashcards to master Triangles
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Define an equilateral triangle and state its key property regarding angles.
An equilateral triangle has three sides of equal length. All three interior angles are also equal, each measuring 60 degrees.
What is an isosceles triangle, and what is significant about its base angles?
An isosceles triangle has two sides of equal length. The angles opposite these equal sides (the base angles) are also equal.
Describe a scalene triangle and how it differs from equilateral and isosceles triangles.
A scalene triangle has all three sides of different lengths. Consequently, all three interior angles are also different sizes, unlike equilateral or isosceles triangles.
State the angle sum property for any triangle and illustrate with an example.
The sum of the interior angles in any triangle is always 180 degrees.
Explain the SSS congruence criterion for triangles. Provide an example.
SSS (Side-Side-Side) states that if all three sides of one triangle are equal in length to the corresponding three sides of another triangle, then the two triangles are congruent. Therefore, they are identical.
Explain the SAS congruence criterion for triangles, including what 'included angle' means.
SAS (Side-Angle-Side) states that if two sides and the included angle (the angle between those two sides) of one triangle are equal to the corresponding two sides and included angle of another triangle, then the two triangles are congruent.
Explain the ASA congruence criterion for triangles, including what 'included side' means.
ASA (Angle-Side-Angle) states that if two angles and the included side (the side between those two angles) of one triangle are equal to the corresponding two angles and included side of another triangle, then the two triangles are congruent.
Explain the RHS congruence criterion for right-angled triangles.
RHS (Right angle-Hypotenuse-Side) states that if the hypotenuse and one side of a right-angled triangle are equal to the hypotenuse and corresponding side of another right-angled triangle, then the two triangles are congruent.
Triangle ABC has angles A = 60°, B = 80°. Calculate the measure of angle C.
Since the angles in a triangle sum to 180°, C = 180° - A - B = 180° - 60° - 80° = 40°. Angle C measures 40 degrees.
Two triangles have sides AB = DE, BC = EF, and CA = FD. Are the triangles congruent? Which congruence criterion applies?
Yes, the triangles are congruent. The SSS (Side-Side-Side) congruence criterion applies, as all three sides of one triangle are equal in length to the corresponding sides of the other.
Key Questions: Triangles
Define an equilateral triangle and state its key property regarding angles.
An equilateral triangle has three sides of equal length. All three interior angles are also equal, each measuring 60 degrees.
What is an isosceles triangle, and what is significant about its base angles?
An isosceles triangle has two sides of equal length. The angles opposite these equal sides (the base angles) are also equal.
Describe a scalene triangle and how it differs from equilateral and isosceles triangles.
A scalene triangle has all three sides of different lengths. Consequently, all three interior angles are also different sizes, unlike equilateral or isosceles triangles.
Explain the SSS congruence criterion for triangles. Provide an example.
SSS (Side-Side-Side) states that if all three sides of one triangle are equal in length to the corresponding three sides of another triangle, then the two triangles are congruent. Therefore, they are identical.
Explain the SAS congruence criterion for triangles, including what 'included angle' means.
SAS (Side-Angle-Side) states that if two sides and the included angle (the angle between those two sides) of one triangle are equal to the corresponding two sides and included angle of another triangle, then the two triangles are congruent.
About Triangles (4.4)
These 10 flashcards cover everything you need to know about Triangles for your Cambridge IGCSE Mathematics (0580) exam. Each card is designed based on the official syllabus requirements.
What You'll Learn
- 7 Definitions - Key terms and their precise meanings that examiners expect
- 1 Key Concepts - Core ideas and principles from the 0580 syllabus
How to Study Effectively
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Continue Learning
After mastering Triangles, explore these related topics:
- 4.3 Parallel lines - 10 flashcards
- 4.5 Quadrilaterals - 9 flashcards
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