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Finding the Fourth Proportional to 420.76, 631.53 and 258.76

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Solution

The fourth proportional to 420.76, 631.53 and 258.76 is: 388.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.76 : 631.53 = 258.76 : x
  2. Step 2: Convert to fraction form
    420.76/631.53 = 258.76/x
  3. Step 3: Cross multiply
    420.76x = 631.53 × 258.76
  4. Step 4: Simplify right side
    420.76x = 163,414.70
  5. Step 5: Solve for x
    x = 163,414.70/420.76
  6. Step 6: Final answer
    x = 388.38

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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.