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Finding the Fourth Proportional to 684.71, 945.10 and 390

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Solution

The fourth proportional to 684.71, 945.10 and 390 is: 538.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.71 : 945.10 = 390 : x
  2. Step 2: Convert to fraction form
    684.71/945.10 = 390/x
  3. Step 3: Cross multiply
    684.71x = 945.10 × 390
  4. Step 4: Simplify right side
    684.71x = 368,589
  5. Step 5: Solve for x
    x = 368,589/684.71
  6. Step 6: Final answer
    x = 538.31

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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.