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Finding the Fourth Proportional to 421.76, 633.60 and 409.28

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Solution

The fourth proportional to 421.76, 633.60 and 409.28 is: 614.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.76 : 633.60 = 409.28 : x
  2. Step 2: Convert to fraction form
    421.76/633.60 = 409.28/x
  3. Step 3: Cross multiply
    421.76x = 633.60 × 409.28
  4. Step 4: Simplify right side
    421.76x = 259,319.81
  5. Step 5: Solve for x
    x = 259,319.81/421.76
  6. Step 6: Final answer
    x = 614.85

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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.