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Finding the Fourth Proportional to 680.70, 1,021.44 and 420.86

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Solution

The fourth proportional to 680.70, 1,021.44 and 420.86 is: 631.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.70 : 1,021.44 = 420.86 : x
  2. Step 2: Convert to fraction form
    680.70/1,021.44 = 420.86/x
  3. Step 3: Cross multiply
    680.70x = 1,021.44 × 420.86
  4. Step 4: Simplify right side
    680.70x = 429,883.24
  5. Step 5: Solve for x
    x = 429,883.24/680.70
  6. Step 6: Final answer
    x = 631.53

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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.