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Finding the Fourth Proportional to 855.09, 1,281.60 and 392.40

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Solution

The fourth proportional to 855.09, 1,281.60 and 392.40 is: 588.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.09 : 1,281.60 = 392.40 : x
  2. Step 2: Convert to fraction form
    855.09/1,281.60 = 392.40/x
  3. Step 3: Cross multiply
    855.09x = 1,281.60 × 392.40
  4. Step 4: Simplify right side
    855.09x = 502,899.84
  5. Step 5: Solve for x
    x = 502,899.84/855.09
  6. Step 6: Final answer
    x = 588.13

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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.