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Finding the Fourth Proportional to 789.89, 1,089.79 and 479.39

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Solution

The fourth proportional to 789.89, 1,089.79 and 479.39 is: 661.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.89 : 1,089.79 = 479.39 : x
  2. Step 2: Convert to fraction form
    789.89/1,089.79 = 479.39/x
  3. Step 3: Cross multiply
    789.89x = 1,089.79 × 479.39
  4. Step 4: Simplify right side
    789.89x = 522,427.78
  5. Step 5: Solve for x
    x = 522,427.78/789.89
  6. Step 6: Final answer
    x = 661.40

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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.