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Finding the Fourth Proportional to 421.64, 628.21 and 405.93

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Solution

The fourth proportional to 421.64, 628.21 and 405.93 is: 604.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.64 : 628.21 = 405.93 : x
  2. Step 2: Convert to fraction form
    421.64/628.21 = 405.93/x
  3. Step 3: Cross multiply
    421.64x = 628.21 × 405.93
  4. Step 4: Simplify right side
    421.64x = 255,009.29
  5. Step 5: Solve for x
    x = 255,009.29/421.64
  6. Step 6: Final answer
    x = 604.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.