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Finding the Fourth Proportional to 291.53, 402.31 and 208.78

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Solution

The fourth proportional to 291.53, 402.31 and 208.78 is: 288.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.53 : 402.31 = 208.78 : x
  2. Step 2: Convert to fraction form
    291.53/402.31 = 208.78/x
  3. Step 3: Cross multiply
    291.53x = 402.31 × 208.78
  4. Step 4: Simplify right side
    291.53x = 83,994.28
  5. Step 5: Solve for x
    x = 83,994.28/291.53
  6. Step 6: Final answer
    x = 288.12

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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.