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Finding the Fourth Proportional to 345.78, 518.64 and 209.70

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Solution

The fourth proportional to 345.78, 518.64 and 209.70 is: 314.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.78 : 518.64 = 209.70 : x
  2. Step 2: Convert to fraction form
    345.78/518.64 = 209.70/x
  3. Step 3: Cross multiply
    345.78x = 518.64 × 209.70
  4. Step 4: Simplify right side
    345.78x = 108,758.81
  5. Step 5: Solve for x
    x = 108,758.81/345.78
  6. Step 6: Final answer
    x = 314.53

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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.