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Finding the Fourth Proportional to 420.70, 632.40 and 388.30

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Solution

The fourth proportional to 420.70, 632.40 and 388.30 is: 583.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.70 : 632.40 = 388.30 : x
  2. Step 2: Convert to fraction form
    420.70/632.40 = 388.30/x
  3. Step 3: Cross multiply
    420.70x = 632.40 × 388.30
  4. Step 4: Simplify right side
    420.70x = 245,560.92
  5. Step 5: Solve for x
    x = 245,560.92/420.70
  6. Step 6: Final answer
    x = 583.70

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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.