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Finding the Fourth Proportional to 989.88, 1,485.36 and 579.39

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Solution

The fourth proportional to 989.88, 1,485.36 and 579.39 is: 869.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.88 : 1,485.36 = 579.39 : x
  2. Step 2: Convert to fraction form
    989.88/1,485.36 = 579.39/x
  3. Step 3: Cross multiply
    989.88x = 1,485.36 × 579.39
  4. Step 4: Simplify right side
    989.88x = 860,602.73
  5. Step 5: Solve for x
    x = 860,602.73/989.88
  6. Step 6: Final answer
    x = 869.40

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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.