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Finding the Fourth Proportional to 670.86, 1,005.57 and 345.78

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Solution

The fourth proportional to 670.86, 1,005.57 and 345.78 is: 518.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.86 : 1,005.57 = 345.78 : x
  2. Step 2: Convert to fraction form
    670.86/1,005.57 = 345.78/x
  3. Step 3: Cross multiply
    670.86x = 1,005.57 × 345.78
  4. Step 4: Simplify right side
    670.86x = 347,705.99
  5. Step 5: Solve for x
    x = 347,705.99/670.86
  6. Step 6: Final answer
    x = 518.30

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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.