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Finding the Fourth Proportional to 693.55, 1,041.34 and 420.79

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Solution

The fourth proportional to 693.55, 1,041.34 and 420.79 is: 631.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    693.55 : 1,041.34 = 420.79 : x
  2. Step 2: Convert to fraction form
    693.55/1,041.34 = 420.79/x
  3. Step 3: Cross multiply
    693.55x = 1,041.34 × 420.79
  4. Step 4: Simplify right side
    693.55x = 438,180.25
  5. Step 5: Solve for x
    x = 438,180.25/693.55
  6. Step 6: Final answer
    x = 631.79

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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.