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Finding the Fourth Proportional to 430.92, 646.58 and 257.78

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Solution

The fourth proportional to 430.92, 646.58 and 257.78 is: 386.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.92 : 646.58 = 257.78 : x
  2. Step 2: Convert to fraction form
    430.92/646.58 = 257.78/x
  3. Step 3: Cross multiply
    430.92x = 646.58 × 257.78
  4. Step 4: Simplify right side
    430.92x = 166,677.65
  5. Step 5: Solve for x
    x = 166,677.65/430.92
  6. Step 6: Final answer
    x = 386.79

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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.