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Finding the Fourth Proportional to 289.20, 399.40 and 258.68

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Solution

The fourth proportional to 289.20, 399.40 and 258.68 is: 357.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.20 : 399.40 = 258.68 : x
  2. Step 2: Convert to fraction form
    289.20/399.40 = 258.68/x
  3. Step 3: Cross multiply
    289.20x = 399.40 × 258.68
  4. Step 4: Simplify right side
    289.20x = 103,316.79
  5. Step 5: Solve for x
    x = 103,316.79/289.20
  6. Step 6: Final answer
    x = 357.25

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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.