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Finding the Fourth Proportional to 670.21, 1,005.38 and 207.86

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Solution

The fourth proportional to 670.21, 1,005.38 and 207.86 is: 311.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.21 : 1,005.38 = 207.86 : x
  2. Step 2: Convert to fraction form
    670.21/1,005.38 = 207.86/x
  3. Step 3: Cross multiply
    670.21x = 1,005.38 × 207.86
  4. Step 4: Simplify right side
    670.21x = 208,982.83
  5. Step 5: Solve for x
    x = 208,982.83/670.21
  6. Step 6: Final answer
    x = 311.82

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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.