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Finding the Fourth Proportional to 698.87, 1,047.85 and 390.76

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Solution

The fourth proportional to 698.87, 1,047.85 and 390.76 is: 585.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    698.87 : 1,047.85 = 390.76 : x
  2. Step 2: Convert to fraction form
    698.87/1,047.85 = 390.76/x
  3. Step 3: Cross multiply
    698.87x = 1,047.85 × 390.76
  4. Step 4: Simplify right side
    698.87x = 409,450.67
  5. Step 5: Solve for x
    x = 409,450.67/698.87
  6. Step 6: Final answer
    x = 585.88

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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.