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Finding the Fourth Proportional to 1,379.76, 2,069.70 and 405.96

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Solution

The fourth proportional to 1,379.76, 2,069.70 and 405.96 is: 608.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.76 : 2,069.70 = 405.96 : x
  2. Step 2: Convert to fraction form
    1,379.76/2,069.70 = 405.96/x
  3. Step 3: Cross multiply
    1,379.76x = 2,069.70 × 405.96
  4. Step 4: Simplify right side
    1,379.76x = 840,215.41
  5. Step 5: Solve for x
    x = 840,215.41/1,379.76
  6. Step 6: Final answer
    x = 608.96

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.