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Finding the Fourth Proportional to 685.01, 945.07 and 390.20

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Solution

The fourth proportional to 685.01, 945.07 and 390.20 is: 538.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.01 : 945.07 = 390.20 : x
  2. Step 2: Convert to fraction form
    685.01/945.07 = 390.20/x
  3. Step 3: Cross multiply
    685.01x = 945.07 × 390.20
  4. Step 4: Simplify right side
    685.01x = 368,760.61
  5. Step 5: Solve for x
    x = 368,760.61/685.01
  6. Step 6: Final answer
    x = 538.33

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Double scale
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1.5x scale

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.