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Finding the Fourth Proportional to 500.78, 688.60 and 485.40

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Solution

The fourth proportional to 500.78, 688.60 and 485.40 is: 667.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.78 : 688.60 = 485.40 : x
  2. Step 2: Convert to fraction form
    500.78/688.60 = 485.40/x
  3. Step 3: Cross multiply
    500.78x = 688.60 × 485.40
  4. Step 4: Simplify right side
    500.78x = 334,246.44
  5. Step 5: Solve for x
    x = 334,246.44/500.78
  6. Step 6: Final answer
    x = 667.45

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.