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Finding the Fourth Proportional to 420.71, 630.72 and 258.35

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Solution

The fourth proportional to 420.71, 630.72 and 258.35 is: 387.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.71 : 630.72 = 258.35 : x
  2. Step 2: Convert to fraction form
    420.71/630.72 = 258.35/x
  3. Step 3: Cross multiply
    420.71x = 630.72 × 258.35
  4. Step 4: Simplify right side
    420.71x = 162,943.36
  5. Step 5: Solve for x
    x = 162,943.36/420.71
  6. Step 6: Final answer
    x = 387.31

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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.