Question:medium

"If two triangles are congruent, then their areas are equal." is the given statement, then the contrapositive of the inverse of the given statement is

Show Hint

Here is an amazing shortcut in mathematical logic: taking the contrapositive of any statement flips its order but preserves its logical truth value. The contrapositive of an inverse ($\sim p \rightarrow \sim q$) will always simplify right back to the original converse statement ($q \rightarrow p$)!
Updated On: Jun 12, 2026
  • If two triangles are not congruent, then their areas are equal.
  • If two triangles are not congruent, then their areas are not equal.
  • If areas of two triangles are equal, then they are congruent.
  • If areas of two triangles are not equal, then they are congruent.
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Name the parts of the statement.
Let $p$: the two triangles are congruent, and $q$: their areas are equal. The original statement reads $p\rightarrow q$.
Step 2: Recall the inverse rule.
The inverse of $p\rightarrow q$ negates both sides without swapping, giving $\sim p\rightarrow\sim q$.
Step 3: Write the inverse explicitly.
So the inverse is $\sim p\rightarrow\sim q$, that is, if the triangles are not congruent then their areas are not equal.
Step 4: Recall the contrapositive rule.
The contrapositive of any conditional $A\rightarrow B$ is $\sim B\rightarrow\sim A$, swapping the two parts and negating each.
Step 5: Apply it to the inverse.
Treating the inverse as $A\rightarrow B$ with $A=\sim p$ and $B=\sim q$, its contrapositive is $\sim(\sim q)\rightarrow\sim(\sim p)$. Using double negation, $\sim(\sim q)=q$ and $\sim(\sim p)=p$, so this is simply $q\rightarrow p$.
Step 6: Translate back to words.
The statement $q\rightarrow p$ reads: if areas of two triangles are equal, then they are congruent. That is option (3).
\[ \boxed{q\rightarrow p:\ \text{equal areas} \Rightarrow \text{congruent}} \]
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