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Finding the Fourth Proportional to 855.64, 1,285.28 and 613.72

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Solution

The fourth proportional to 855.64, 1,285.28 and 613.72 is: 921.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.64 : 1,285.28 = 613.72 : x
  2. Step 2: Convert to fraction form
    855.64/1,285.28 = 613.72/x
  3. Step 3: Cross multiply
    855.64x = 1,285.28 × 613.72
  4. Step 4: Simplify right side
    855.64x = 788,802.04
  5. Step 5: Solve for x
    x = 788,802.04/855.64
  6. Step 6: Final answer
    x = 921.89

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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.