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Finding the Fourth Proportional to 785.69, 1,178.42 and 208.61

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Solution

The fourth proportional to 785.69, 1,178.42 and 208.61 is: 312.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.69 : 1,178.42 = 208.61 : x
  2. Step 2: Convert to fraction form
    785.69/1,178.42 = 208.61/x
  3. Step 3: Cross multiply
    785.69x = 1,178.42 × 208.61
  4. Step 4: Simplify right side
    785.69x = 245,829.15
  5. Step 5: Solve for x
    x = 245,829.15/785.69
  6. Step 6: Final answer
    x = 312.88

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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.