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Finding the Fourth Proportional to 685.02, 945.25 and 390.20

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Solution

The fourth proportional to 685.02, 945.25 and 390.20 is: 538.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.02 : 945.25 = 390.20 : x
  2. Step 2: Convert to fraction form
    685.02/945.25 = 390.20/x
  3. Step 3: Cross multiply
    685.02x = 945.25 × 390.20
  4. Step 4: Simplify right side
    685.02x = 368,836.55
  5. Step 5: Solve for x
    x = 368,836.55/685.02
  6. Step 6: Final answer
    x = 538.43

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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.