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Finding the Fourth Proportional to 285.72, 428.18 and 208.86

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Solution

The fourth proportional to 285.72, 428.18 and 208.86 is: 312.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.72 : 428.18 = 208.86 : x
  2. Step 2: Convert to fraction form
    285.72/428.18 = 208.86/x
  3. Step 3: Cross multiply
    285.72x = 428.18 × 208.86
  4. Step 4: Simplify right side
    285.72x = 89,428.63
  5. Step 5: Solve for x
    x = 89,428.63/285.72
  6. Step 6: Final answer
    x = 312.99

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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.