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Finding the Fourth Proportional to 785.57, 1,178.39 and 208.45

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Solution

The fourth proportional to 785.57, 1,178.39 and 208.45 is: 312.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.57 : 1,178.39 = 208.45 : x
  2. Step 2: Convert to fraction form
    785.57/1,178.39 = 208.45/x
  3. Step 3: Cross multiply
    785.57x = 1,178.39 × 208.45
  4. Step 4: Simplify right side
    785.57x = 245,628.46
  5. Step 5: Solve for x
    x = 245,628.46/785.57
  6. Step 6: Final answer
    x = 312.68

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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.