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Finding the Fourth Proportional to 612.64, 917.38 and 427.28

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Solution

The fourth proportional to 612.64, 917.38 and 427.28 is: 639.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.64 : 917.38 = 427.28 : x
  2. Step 2: Convert to fraction form
    612.64/917.38 = 427.28/x
  3. Step 3: Cross multiply
    612.64x = 917.38 × 427.28
  4. Step 4: Simplify right side
    612.64x = 391,978.13
  5. Step 5: Solve for x
    x = 391,978.13/612.64
  6. Step 6: Final answer
    x = 639.82

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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.