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Finding the Fourth Proportional to 328.89, 493.36 and 85.42

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Solution

The fourth proportional to 328.89, 493.36 and 85.42 is: 128.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    328.89 : 493.36 = 85.42 : x
  2. Step 2: Convert to fraction form
    328.89/493.36 = 85.42/x
  3. Step 3: Cross multiply
    328.89x = 493.36 × 85.42
  4. Step 4: Simplify right side
    328.89x = 42,143.21
  5. Step 5: Solve for x
    x = 42,143.21/328.89
  6. Step 6: Final answer
    x = 128.14

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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.