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Finding the Fourth Proportional to 647.60, 971.40 and 439.70

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Solution

The fourth proportional to 647.60, 971.40 and 439.70 is: 659.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.60 : 971.40 = 439.70 : x
  2. Step 2: Convert to fraction form
    647.60/971.40 = 439.70/x
  3. Step 3: Cross multiply
    647.60x = 971.40 × 439.70
  4. Step 4: Simplify right side
    647.60x = 427,124.58
  5. Step 5: Solve for x
    x = 427,124.58/647.60
  6. Step 6: Final answer
    x = 659.55

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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.