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Finding the Fourth Proportional to 401.78, 553.53 and 308.42

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Solution

The fourth proportional to 401.78, 553.53 and 308.42 is: 424.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    401.78 : 553.53 = 308.42 : x
  2. Step 2: Convert to fraction form
    401.78/553.53 = 308.42/x
  3. Step 3: Cross multiply
    401.78x = 553.53 × 308.42
  4. Step 4: Simplify right side
    401.78x = 170,719.72
  5. Step 5: Solve for x
    x = 170,719.72/401.78
  6. Step 6: Final answer
    x = 424.91

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.