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Finding the Fourth Proportional to 514.78, 709.78 and 421.30

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Solution

The fourth proportional to 514.78, 709.78 and 421.30 is: 580.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    514.78 : 709.78 = 421.30 : x
  2. Step 2: Convert to fraction form
    514.78/709.78 = 421.30/x
  3. Step 3: Cross multiply
    514.78x = 709.78 × 421.30
  4. Step 4: Simplify right side
    514.78x = 299,030.31
  5. Step 5: Solve for x
    x = 299,030.31/514.78
  6. Step 6: Final answer
    x = 580.89

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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.