I think that first you need to understand what CPCTC is used for.
Let's start with the definition of congruent triangles.
Definition of congruent triangles
Two triangles are congruent if each side of one triangle is congruent to a corresponding side of the other triangle and each angle of one triangle is congruent to a corresponding angle of the other triangle.
A definition works two ways.
1) If you are told the sides and angles of one triangle are congruent to the corresponding sides and angle of a second triangle, then you can conclude the triangles are congruent.
2) If you are told the triangles are congruent, then you can conclude 6 statements of congruence, 3 for sides and 3 for angles.
Now let's see what CPCTC is and how it works.
CPCTC stands for "corresponding parts of congruent triangles are congruent."
The way it works is this. You can prove triangles congruent by knowing fewer that 6 statements of congruence. You can use ASA, SAS, AAS, SSS, etc. Once you prove two triangles congruent, then by the definition of congruent triangles, there are 6 congruent statements. That is where CPCTC comes in. Once you prove the triangles congruent, then you can conclude two corresponding sides or two corresponding angles are congruent by CPCTC. These two corresponding parts were not involved in proving the triangles congruent.
Problem 1.
Statements Reasons
1. Seg. AD perp. seg. BC 1. Given
2. <ADB & <ADC are right angles 2. Def. of perp. lines
3. <ADB is congr. <ADC 3. All right angles are congruent
4. Seg. BD is congr. seg CD 4. Given
5. Seg. AD is congr. seg. AD 5. Congruence of segments is reflexive
6. Tr. ABD is congr. tr. ACD 6. SAS
7. Seg. AB is congr. seg. AC 7. CPCTC
Eduardo is packing 12 pairs of mismatched socks for his trip.
Answer:
$3600
Step-by-step explanation:
In each case, the repair cost exceeded the deductible, so your out-of-pocket cost for 2 repairs is ...
2 × $1050 = $2100
In addition, you had to pay the premium of $750 per 6-month period, or $1500 per year, so your total was ...
$2100 +1500 = $3600 . . . out-of-pocket total
Answer:
x + 0.07x ≥ 30
Step-by-step explanation:
A sum is terms separated by a plus sign.
"Is at least" means "is greater than or equal to."
7% as a decimal fraction is 0.07.
"Of" means "times."
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In consideration of the above, you have ...
x plus 7% of x is at least 30
x + 0.07x ≥ 30 . . . . . using math symbols