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Finding the Fourth Proportional to 869.84, 1,305.12 and 485

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Solution

The fourth proportional to 869.84, 1,305.12 and 485 is: 727.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.84 : 1,305.12 = 485 : x
  2. Step 2: Convert to fraction form
    869.84/1,305.12 = 485/x
  3. Step 3: Cross multiply
    869.84x = 1,305.12 × 485
  4. Step 4: Simplify right side
    869.84x = 632,983.20
  5. Step 5: Solve for x
    x = 632,983.20/869.84
  6. Step 6: Final answer
    x = 727.70

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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.