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Finding the Fourth Proportional to 285.39, 428.09 and 256.77

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Solution

The fourth proportional to 285.39, 428.09 and 256.77 is: 385.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.39 : 428.09 = 256.77 : x
  2. Step 2: Convert to fraction form
    285.39/428.09 = 256.77/x
  3. Step 3: Cross multiply
    285.39x = 428.09 × 256.77
  4. Step 4: Simplify right side
    285.39x = 109,919.39
  5. Step 5: Solve for x
    x = 109,919.39/285.39
  6. Step 6: Final answer
    x = 385.16

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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.