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Finding the Fourth Proportional to 990.52, 1,485.32 and 579.78

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Solution

The fourth proportional to 990.52, 1,485.32 and 579.78 is: 869.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.52 : 1,485.32 = 579.78 : x
  2. Step 2: Convert to fraction form
    990.52/1,485.32 = 579.78/x
  3. Step 3: Cross multiply
    990.52x = 1,485.32 × 579.78
  4. Step 4: Simplify right side
    990.52x = 861,155.93
  5. Step 5: Solve for x
    x = 861,155.93/990.52
  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.