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Finding the Fourth Proportional to 698.40, 1,047.60 and 657.90

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Solution

The fourth proportional to 698.40, 1,047.60 and 657.90 is: 986.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    698.40 : 1,047.60 = 657.90 : x
  2. Step 2: Convert to fraction form
    698.40/1,047.60 = 657.90/x
  3. Step 3: Cross multiply
    698.40x = 1,047.60 × 657.90
  4. Step 4: Simplify right side
    698.40x = 689,216.04
  5. Step 5: Solve for x
    x = 689,216.04/698.40
  6. Step 6: Final answer
    x = 986.85

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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.