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Finding the Fourth Proportional to 289.36, 399.23 and 215.70

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Solution

The fourth proportional to 289.36, 399.23 and 215.70 is: 297.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.36 : 399.23 = 215.70 : x
  2. Step 2: Convert to fraction form
    289.36/399.23 = 215.70/x
  3. Step 3: Cross multiply
    289.36x = 399.23 × 215.70
  4. Step 4: Simplify right side
    289.36x = 86,112.14
  5. Step 5: Solve for x
    x = 86,112.14/289.36
  6. Step 6: Final answer
    x = 297.60

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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.