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Finding the Fourth Proportional to 421.30, 628.36 and 409.75

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Solution

The fourth proportional to 421.30, 628.36 and 409.75 is: 611.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.30 : 628.36 = 409.75 : x
  2. Step 2: Convert to fraction form
    421.30/628.36 = 409.75/x
  3. Step 3: Cross multiply
    421.30x = 628.36 × 409.75
  4. Step 4: Simplify right side
    421.30x = 257,470.51
  5. Step 5: Solve for x
    x = 257,470.51/421.30
  6. Step 6: Final answer
    x = 611.13

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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.