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Finding the Fourth Proportional to 1,078.70, 1,618.20 and 429.29

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Solution

The fourth proportional to 1,078.70, 1,618.20 and 429.29 is: 643.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.70 : 1,618.20 = 429.29 : x
  2. Step 2: Convert to fraction form
    1,078.70/1,618.20 = 429.29/x
  3. Step 3: Cross multiply
    1,078.70x = 1,618.20 × 429.29
  4. Step 4: Simplify right side
    1,078.70x = 694,668.99
  5. Step 5: Solve for x
    x = 694,668.99/1,078.70
  6. Step 6: Final answer
    x = 643.99

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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.