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Finding the Fourth Proportional to 990.85, 1,487.42 and 580.28

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Solution

The fourth proportional to 990.85, 1,487.42 and 580.28 is: 871.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.85 : 1,487.42 = 580.28 : x
  2. Step 2: Convert to fraction form
    990.85/1,487.42 = 580.28/x
  3. Step 3: Cross multiply
    990.85x = 1,487.42 × 580.28
  4. Step 4: Simplify right side
    990.85x = 863,125.25
  5. Step 5: Solve for x
    x = 863,125.25/990.85
  6. Step 6: Final answer
    x = 871.10

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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.