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Finding the Fourth Proportional to 839.12, 1,258.65 and 345.78

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Solution

The fourth proportional to 839.12, 1,258.65 and 345.78 is: 518.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.12 : 1,258.65 = 345.78 : x
  2. Step 2: Convert to fraction form
    839.12/1,258.65 = 345.78/x
  3. Step 3: Cross multiply
    839.12x = 1,258.65 × 345.78
  4. Step 4: Simplify right side
    839.12x = 435,216.00
  5. Step 5: Solve for x
    x = 435,216.00/839.12
  6. Step 6: Final answer
    x = 518.66

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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.