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Finding the Fourth Proportional to 869.98, 1,305.20 and 431.36

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Solution

The fourth proportional to 869.98, 1,305.20 and 431.36 is: 647.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.98 : 1,305.20 = 431.36 : x
  2. Step 2: Convert to fraction form
    869.98/1,305.20 = 431.36/x
  3. Step 3: Cross multiply
    869.98x = 1,305.20 × 431.36
  4. Step 4: Simplify right side
    869.98x = 563,011.07
  5. Step 5: Solve for x
    x = 563,011.07/869.98
  6. Step 6: Final answer
    x = 647.15

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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.