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Finding the Fourth Proportional to 289.40, 431.87 and 258.64

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Solution

The fourth proportional to 289.40, 431.87 and 258.64 is: 385.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.40 : 431.87 = 258.64 : x
  2. Step 2: Convert to fraction form
    289.40/431.87 = 258.64/x
  3. Step 3: Cross multiply
    289.40x = 431.87 × 258.64
  4. Step 4: Simplify right side
    289.40x = 111,698.86
  5. Step 5: Solve for x
    x = 111,698.86/289.40
  6. Step 6: Final answer
    x = 385.97

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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.