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Finding the Fourth Proportional to 430.65, 641.79 and 421.34

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Solution

The fourth proportional to 430.65, 641.79 and 421.34 is: 627.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.65 : 641.79 = 421.34 : x
  2. Step 2: Convert to fraction form
    430.65/641.79 = 421.34/x
  3. Step 3: Cross multiply
    430.65x = 641.79 × 421.34
  4. Step 4: Simplify right side
    430.65x = 270,408.59
  5. Step 5: Solve for x
    x = 270,408.59/430.65
  6. Step 6: Final answer
    x = 627.91

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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.