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Finding the Fourth Proportional to 656.70, 979.10 and 639.60

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Solution

The fourth proportional to 656.70, 979.10 and 639.60 is: 953.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.70 : 979.10 = 639.60 : x
  2. Step 2: Convert to fraction form
    656.70/979.10 = 639.60/x
  3. Step 3: Cross multiply
    656.70x = 979.10 × 639.60
  4. Step 4: Simplify right side
    656.70x = 626,229.16
  5. Step 5: Solve for x
    x = 626,229.16/656.70
  6. Step 6: Final answer
    x = 953.60

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.