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Finding the Fourth Proportional to 401.20, 553.53 and 307.78

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Solution

The fourth proportional to 401.20, 553.53 and 307.78 is: 424.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    401.20 : 553.53 = 307.78 : x
  2. Step 2: Convert to fraction form
    401.20/553.53 = 307.78/x
  3. Step 3: Cross multiply
    401.20x = 553.53 × 307.78
  4. Step 4: Simplify right side
    401.20x = 170,365.46
  5. Step 5: Solve for x
    x = 170,365.46/401.20
  6. Step 6: Final answer
    x = 424.64

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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.