NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 3: Pair of Linear Equations in Two Variables - Exercise 3.3
Question 15

Question. 15

The angles of a triangle are \(x\), \(y\), and \(40^\circ\). Their difference \(|x - y|\) is \(30^\circ\). Find \(x\) and \(y\).

Answer:

\(x = 85^\circ\), \(y = 55^\circ\) (or vice versa).

Detailed Answer with Explanation:

Step 1: In any triangle, the sum of the three angles is always \(180^\circ\).

So,

\(x + y + 40 = 180\)

\(x + y = 180 - 40\)

\(x + y = 140\)

Step 2: We are also told that the difference between \(x\) and \(y\) is \(30^\circ\).

This means:

\(|x - y| = 30\)

Step 3: Now we have two equations:

1) \(x + y = 140\)

2) \(|x - y| = 30\)

Step 4: Let us assume \(x > y\). Then \(x - y = 30\).

Step 5: Add the two equations:

\((x + y) + (x - y) = 140 + 30\)

\(2x = 170\)

\(x = 85\)

Step 6: Put \(x = 85\) in equation (1):

\(85 + y = 140\)

\(y = 55\)

Step 7: If we had assumed \(y > x\), then we would get \(y = 85\) and \(x = 55\).

Final Answer: The two angles are \(85^\circ\) and \(55^\circ\).

NCERT Exemplar Solutions Class 10 – Mathematics – CHAPTER 3: Pair of Linear Equations in Two Variables – Exercise 3.3 | Detailed Answers