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Finding the Fourth Proportional to 911.36, 1,365.90 and 390.75

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Solution

The fourth proportional to 911.36, 1,365.90 and 390.75 is: 585.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.36 : 1,365.90 = 390.75 : x
  2. Step 2: Convert to fraction form
    911.36/1,365.90 = 390.75/x
  3. Step 3: Cross multiply
    911.36x = 1,365.90 × 390.75
  4. Step 4: Simplify right side
    911.36x = 533,725.43
  5. Step 5: Solve for x
    x = 533,725.43/911.36
  6. Step 6: Final answer
    x = 585.64

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.