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Finding the Fourth Proportional to 685.06, 945.39 and 390.35

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Solution

The fourth proportional to 685.06, 945.39 and 390.35 is: 538.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.06 : 945.39 = 390.35 : x
  2. Step 2: Convert to fraction form
    685.06/945.39 = 390.35/x
  3. Step 3: Cross multiply
    685.06x = 945.39 × 390.35
  4. Step 4: Simplify right side
    685.06x = 369,032.99
  5. Step 5: Solve for x
    x = 369,032.99/685.06
  6. Step 6: Final answer
    x = 538.69

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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.