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Finding the Fourth Proportional to 291.78, 438.13 and 278.79

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Solution

The fourth proportional to 291.78, 438.13 and 278.79 is: 418.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.78 : 438.13 = 278.79 : x
  2. Step 2: Convert to fraction form
    291.78/438.13 = 278.79/x
  3. Step 3: Cross multiply
    291.78x = 438.13 × 278.79
  4. Step 4: Simplify right side
    291.78x = 122,147.10
  5. Step 5: Solve for x
    x = 122,147.10/291.78
  6. Step 6: Final answer
    x = 418.63

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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.