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Finding the Fourth Proportional to 289.60, 399.36 and 285.60

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Solution

The fourth proportional to 289.60, 399.36 and 285.60 is: 393.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.60 : 399.36 = 285.60 : x
  2. Step 2: Convert to fraction form
    289.60/399.36 = 285.60/x
  3. Step 3: Cross multiply
    289.60x = 399.36 × 285.60
  4. Step 4: Simplify right side
    289.60x = 114,057.22
  5. Step 5: Solve for x
    x = 114,057.22/289.60
  6. Step 6: Final answer
    x = 393.84

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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.