GRE math formulas Flashcards
What rule guides the length of all triangles’ sides?
The length of each side must be less than the sum of the other two sides.
How do you find the sum of interior angles in a polygon?
n= number of sides (n-2)(180)= sum of interior angles
What is an isosceles triangle?
At least two sides congruent
What is the Pythagorean theorem?
a^2+b^2= c^2
An equilateral triangle divided in half becomes what?
30* 60* 90* triangle
What is the relationship between length of sides in a 30-60-90 triangle?
Hypotenuse is twice the shorter leg
What is the area of a triangle?
A= (bh)/2
What are congruent triangles?
Same shape and size
What are similar triangles?
Same shape but not necessarily same size
How do you know if two triangles are congruent?
•If the three sides of one are congruent to the three sides of another then the triangles are congruent
•if two sides and the included angle are congruent
If two angles and the included side
What is the area of a parallelogram?
A=bh
Why is the area of a trapezoid?
A= 1/2(b1+b2)(h)
What is the circumference of a circle?
C=2•pie•r
Hat is the area of a circle?
A=pie•r^2
What is the volume of a rectangular solid?
V=lwh
