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Finding the Fourth Proportional to 430.31, 643.95 and 257.07

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Solution

The fourth proportional to 430.31, 643.95 and 257.07 is: 384.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.31 : 643.95 = 257.07 : x
  2. Step 2: Convert to fraction form
    430.31/643.95 = 257.07/x
  3. Step 3: Cross multiply
    430.31x = 643.95 × 257.07
  4. Step 4: Simplify right side
    430.31x = 165,542.64
  5. Step 5: Solve for x
    x = 165,542.64/430.31
  6. Step 6: Final answer
    x = 384.70

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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.