Question

The figure below shows a rectangle ABCD having diagonals AC and DB:

Answer 1

Jimmy wrote the following proof to show that the diagonals of rectangle ABCD are congruent:


Jimmy's proof:
Statement 1: In triangle ADC and BCD, AD = BC (opposite sides of a rectangle are congruent)
Statement 2: Angle ADC = Angle BCD (angles of a rectangle are 90°)
Statement 3: DC=DC (transitive property of equality)
Statement 4: Triangle ADC and BCD are congruent (by SAS postulate)
Statement 5: AC = BD (by CPCTC)

Answer 2

Which statement in Jimmy's proof has an error?

Statement 2

Statement 3

Statement 1

Statement 4

Answer 3

@aric200

Answer 4

@zepdrix

Answer 5

@KingGeorge @mathstudent55

Answer 6

DC = DC is reflexive property NOT transitive property.

Answer 7

yuuppp...dc=dc is reflexive....

Answer 8

statement 4 is error
because its not a SAS postulate ,it should RHS postulate

Answer 9

First error in statement 3. Next error in statement 4.

Answer 10

So statement 3 or 4?

Answer 11

DC=DC is common only .statement 3 is error