Multiple choice

What approximate value should come in place of question mark in the following questions? (You are not expected to calculate the exact value). ( (67.8)^2 - (43.2)^2 - (12.9)^2 = ? )

  1. 2600

  2. 2700

  3. 2800

  4. 2500

  5. 2900
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using the difference of squares formula: a² - b² = (a+b)(a-b). So (67.8)² - (43.2)² = (67.8+43.2)(67.8-43.2) = 111 × 24.6 = 2730.6. Then subtract (12.9)² = 166.41. Total: 2730.6 - 166.41 = 2564.19 ≈ 2600. Option A (2600) is the closest approximation.

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