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Finding the Fourth Proportional to 619.70, 869.20 and 619.70

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Solution

The fourth proportional to 619.70, 869.20 and 619.70 is: 869.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    619.70 : 869.20 = 619.70 : x
  2. Step 2: Convert to fraction form
    619.70/869.20 = 619.70/x
  3. Step 3: Cross multiply
    619.70x = 869.20 × 619.70
  4. Step 4: Simplify right side
    619.70x = 538,643.24
  5. Step 5: Solve for x
    x = 538,643.24/619.70
  6. Step 6: Final answer
    x = 869.20

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Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.