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Finding the Fourth Proportional to 628.56, 939.60 and 518.40

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Solution

The fourth proportional to 628.56, 939.60 and 518.40 is: 774.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    628.56 : 939.60 = 518.40 : x
  2. Step 2: Convert to fraction form
    628.56/939.60 = 518.40/x
  3. Step 3: Cross multiply
    628.56x = 939.60 × 518.40
  4. Step 4: Simplify right side
    628.56x = 487,088.64
  5. Step 5: Solve for x
    x = 487,088.64/628.56
  6. Step 6: Final answer
    x = 774.93

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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.