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Finding the Fourth Proportional to 285.35, 428.13 and 139.16

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Solution

The fourth proportional to 285.35, 428.13 and 139.16 is: 208.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.35 : 428.13 = 139.16 : x
  2. Step 2: Convert to fraction form
    285.35/428.13 = 139.16/x
  3. Step 3: Cross multiply
    285.35x = 428.13 × 139.16
  4. Step 4: Simplify right side
    285.35x = 59,579.64
  5. Step 5: Solve for x
    x = 59,579.64/285.35
  6. Step 6: Final answer
    x = 208.80

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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.