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Finding the Fourth Proportional to 989.64, 1,485.68 and 578.97

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Solution

The fourth proportional to 989.64, 1,485.68 and 578.97 is: 869.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.64 : 1,485.68 = 578.97 : x
  2. Step 2: Convert to fraction form
    989.64/1,485.68 = 578.97/x
  3. Step 3: Cross multiply
    989.64x = 1,485.68 × 578.97
  4. Step 4: Simplify right side
    989.64x = 860,161.25
  5. Step 5: Solve for x
    x = 860,161.25/989.64
  6. Step 6: Final answer
    x = 869.17

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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.