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Finding the Fourth Proportional to 285.81, 428.72 and 90.81

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Solution

The fourth proportional to 285.81, 428.72 and 90.81 is: 136.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.81 : 428.72 = 90.81 : x
  2. Step 2: Convert to fraction form
    285.81/428.72 = 90.81/x
  3. Step 3: Cross multiply
    285.81x = 428.72 × 90.81
  4. Step 4: Simplify right side
    285.81x = 38,933.22
  5. Step 5: Solve for x
    x = 38,933.22/285.81
  6. Step 6: Final answer
    x = 136.22

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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.