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Finding the Fourth Proportional to 1,078.78, 1,618.44 and 429.70

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Solution

The fourth proportional to 1,078.78, 1,618.44 and 429.70 is: 644.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.78 : 1,618.44 = 429.70 : x
  2. Step 2: Convert to fraction form
    1,078.78/1,618.44 = 429.70/x
  3. Step 3: Cross multiply
    1,078.78x = 1,618.44 × 429.70
  4. Step 4: Simplify right side
    1,078.78x = 695,443.67
  5. Step 5: Solve for x
    x = 695,443.67/1,078.78
  6. Step 6: Final answer
    x = 644.66

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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.