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Finding the Fourth Proportional to 839.65, 1,258.72 and 429.29

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Solution

The fourth proportional to 839.65, 1,258.72 and 429.29 is: 643.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.65 : 1,258.72 = 429.29 : x
  2. Step 2: Convert to fraction form
    839.65/1,258.72 = 429.29/x
  3. Step 3: Cross multiply
    839.65x = 1,258.72 × 429.29
  4. Step 4: Simplify right side
    839.65x = 540,355.91
  5. Step 5: Solve for x
    x = 540,355.91/839.65
  6. Step 6: Final answer
    x = 643.55

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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.