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Finding the Fourth Proportional to 438.60, 657.90 and 427.80

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Solution

The fourth proportional to 438.60, 657.90 and 427.80 is: 641.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.60 : 657.90 = 427.80 : x
  2. Step 2: Convert to fraction form
    438.60/657.90 = 427.80/x
  3. Step 3: Cross multiply
    438.60x = 657.90 × 427.80
  4. Step 4: Simplify right side
    438.60x = 281,449.62
  5. Step 5: Solve for x
    x = 281,449.62/438.60
  6. Step 6: Final answer
    x = 641.70

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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.