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Finding the Fourth Proportional to 616.40, 851.67 and 420.78

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Solution

The fourth proportional to 616.40, 851.67 and 420.78 is: 581.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    616.40 : 851.67 = 420.78 : x
  2. Step 2: Convert to fraction form
    616.40/851.67 = 420.78/x
  3. Step 3: Cross multiply
    616.40x = 851.67 × 420.78
  4. Step 4: Simplify right side
    616.40x = 358,365.70
  5. Step 5: Solve for x
    x = 358,365.70/616.40
  6. Step 6: Final answer
    x = 581.39

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1.5x scale

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.