Is the perimeter of triangle ABC greater than 6 cm?(1) One side of tri...
Steps 1 & 2: Understand Question and Draw Inferences
Let’s say the sides of the triangle are a, b, and c.
Let the perimeter of the triangle be X.
Thus, X = a + b + c
We need to find whether X > 6
Since we don’t have any other information, let’s move on to the analysis of the statement 1.
Step 3: Analyse Statement 1
Statement 1 says: One side of triangle ABC measures 3 cm.
Let’s assume a = 3 cm
Now, we know that the sum of two sides of a triangle is always greater than the third side.
So, we can write:
b + c > a
Adding a to both sides of this inequality, we get:
a + b + c > 2a
That is, X > 2a
Substituting a = 3 cm in this inequality, we get:
X > 6 cm
Thus, Statement 1 alone is sufficient to answer the question.
Step 4: Analyse Statement 2
Statement 2 says: The lengths of the three sides of triangle ABC are consecutive integers.
So, the lengths of the sides are n, (n+1), (n+2) cm, where n is a positive integer.
Perimeter X = n + (n+1) + (n+2)
X = 3n + 3
X = 3(n+1)
Now, we know that the sum of two sides of a triangle is always greater than the third side.
This means, we can write:
n + (n+1) > n + 2
2n + 1 > n + 2
n > 1
Adding 1 to both sides of this inequality:
n + 1 > 2
We know that multiplying both sides of an inequality with a positive number doesn’t change the inequality. Therefore, multiplying both sides of the above inequality with 3:
3(n+1) > 6
This means, X > 6
Thus, Statement 2 alone is sufficient to determine if X > 6
Step 5: Analyse Both Statements Together (if needed)
Since we got the answer to the question in Steps 3 and 4, we don’t need to perform this step.
Answer: Option (D)