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Finding the Fourth Proportional to 289.44, 431.28 and 278.64

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Solution

The fourth proportional to 289.44, 431.28 and 278.64 is: 415.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.44 : 431.28 = 278.64 : x
  2. Step 2: Convert to fraction form
    289.44/431.28 = 278.64/x
  3. Step 3: Cross multiply
    289.44x = 431.28 × 278.64
  4. Step 4: Simplify right side
    289.44x = 120,171.86
  5. Step 5: Solve for x
    x = 120,171.86/289.44
  6. Step 6: Final answer
    x = 415.19

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.