Question 3 of 21beginner🔧 ApplyNumerical2 marks

Find the length of the third side of a triangle having a perimeter of 55 cm and having two sides of length 20 cm and 14 cm, respectively.

Correct Answer

Given: Perimeter = 55 cm, two sides = 20 cm and 14 cm.

Formula: Perimeter = Sum of all three sides.

Substitution: Third side = Perimeter − Sum of two known sides.

Calculation: Sum of two known sides = 20 + 14 = 34 cm Third side = 55 − 34 = 21 cm

Answer: The length of the third side is 21 cm.

Exercise: Figure it Out (Section 1) | Q: 3 | (Page Page 4)
For More Understanding

Explanation

The perimeter of a triangle is the sum of the lengths of all three sides. Given the perimeter and two sides, the third side can be found by subtracting the known sides from the perimeter.

Solution Steps

  1. Identify the given values: Perimeter = 55 cm, two sides = 20 cm and 14 cm.

  2. State the formula: Perimeter = Sum of all three sides.

  3. Set up the equation: Third side = Perimeter − Sum of two known sides.

  4. Calculate the sum of the two known sides: 20 + 14 = 34 cm.

  5. Calculate the third side: 55 − 34 = 21 cm.

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