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Finding the Fourth Proportional to 291.66, 402.20 and 208.78

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Solution

The fourth proportional to 291.66, 402.20 and 208.78 is: 287.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.66 : 402.20 = 208.78 : x
  2. Step 2: Convert to fraction form
    291.66/402.20 = 208.78/x
  3. Step 3: Cross multiply
    291.66x = 402.20 × 208.78
  4. Step 4: Simplify right side
    291.66x = 83,971.32
  5. Step 5: Solve for x
    x = 83,971.32/291.66
  6. Step 6: Final answer
    x = 287.91

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.