Question

The angles of a triangle are in the ratio 3:4:5. The measure of the smallest angle is
A)30digre
B)45digre
C)60digre

Answer 1

Given :

• The angles of a triangle are in the ratio 3:4:5.

To find :

• Smallest angle.

Solution :

Consider,

• 1st angle = 3x°
• 2nd angle = 4x°
• 3rd angle = 5x°

We know,

The sum of 3 angles of a triangle is 180°.

Therefore,

1st angle + 2nd angle + 3rd angle = 180

→ 3x + 4x + 5x = 180

→ 12x = 180

→ x = 180/12

→ x = 15

Then ,

• 1st angle = 3×15 = 45°
• 2nd angle = 4×15 = 60°
• 3rd angle = 5×15 = 75°

Therefore, the smallest angle is 45°.

Answer 2

Question :

The angles of a triangle are in the ratio 3:4:5. The measure of the smallest angle is

A)30 degree

B)45 degree

C)60 degree

Answer :

Ratio given : 3:4:5

Let the 1st angle be = 3x°

Let the 2nd angle be = 4x°

Let the 3rd angle be = 5x°

• As we know the sum of three angle of triangle is 180°

According to the question,

➮1st angle + 2nd angle + 3rd angle = 180°

➮3x° + 4x° + 5x° = 180°

➮12x° = 180°

➮x = 180° ÷ 12°

.°. x = 15°

_____________________....

Now we put the value of x

• 1st angle = 3x° = 3 × 15° = 45°
• 2nd angle = 4x° = 4 × 15° = 60°
• 3rd angle = 5x° = 5 × 15° = 75°

_____________________....

Therefore smallest angle is 45°

• Option B