## 104 terms

### ruler postulate

used to find distance between two points by taking absolute value of difference of their coordinates.

### hypothesis

part of a conditional statement following "if" but not including the word "if." ex: "if you're a girl, then you're hot" the ____ is "you're a girl"

### conclusion

part of conditional statement following "then" but not including the word "then." ex: "if Ke$ha were educated, then she should not be nearly as famous" the _____ is "she would not be nearly as famous."

### biconditional

both conditional and converse are both true. (all geometry definitions can be written as this).

### vertical angles

two angles whose sides form two pairs of opposite rays and they are congruent angles

### deductive reasoning

logical thinking where we use different postulates and theorems, definitions and properties to prove something.

### SSS postulate

if 3 sides of one triangle are congruent to 3 sides of another triangle, triangles are congruent.

### SAS postulate

if 2 sides and included angle of one ∆ are congruent to 2 sides and the included angle of another ∆, triangles are congruent.

### ASA postulate

if 2 angles and the included side of one triangle are congruent to 2 angles and the included side of another ∆, triangles are congruent.

### AAS postulate

if 2 angles and a non-inclined side of 1 ∆ are congruent to 2 angles and non-inclined side of another ∆, triangles are congruent.

### HL theorem

in 2 right triangles, the hypotenuse and leg are congruent to the hypotenuse and leg of the other triangle, triangles are congruent.

### isosceles triangle theorem

if 2 sides of a ∆ are congruent, then the angles opposite those sides are also congruent.

### exterior angle inequality theorem

measure of an exterior angle of a ∆ is greater than the measure of either remote interior angle.

### equivalent

statement and contrapositive are logically equivalent. converse and inverse are logically equivalent.

### indirect proof

a proof in which you 1) assume temporarily the opposite of what you're trying to prove. 2) Reason logically until you reach a contradiction of a known fact. 3) point out that the temp. assumption is false and that the conclusion is true.

### temporary assumption

statement that asks to temporarily assume that the opposite of what you're trying to prove is true.

### SAS inequality

if 2 sides of one ∆ are congruent to 2 sides of another ∆, but the included angle of the first ∆ is larger than the included angle of the second, the third side of the fist ∆ is longer than the third side of the second ∆

### SSS inequality

if 2 sides of a ∆ are congruent to 2 sides of another ∆, but the third side of the first ∆ is longer than the third side of the second ∆, then the included angle of the first ∆ is larger that the included angle of the second ∆.