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Finding the Fourth Proportional to 656.60, 978.91 and 639.77

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Solution

The fourth proportional to 656.60, 978.91 and 639.77 is: 953.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.60 : 978.91 = 639.77 : x
  2. Step 2: Convert to fraction form
    656.60/978.91 = 639.77/x
  3. Step 3: Cross multiply
    656.60x = 978.91 × 639.77
  4. Step 4: Simplify right side
    656.60x = 626,270.76
  5. Step 5: Solve for x
    x = 626,270.76/656.60
  6. Step 6: Final answer
    x = 953.82

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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.