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Finding the Fourth Proportional to 685.33, 945.81 and 390.53

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Solution

The fourth proportional to 685.33, 945.81 and 390.53 is: 538.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.33 : 945.81 = 390.53 : x
  2. Step 2: Convert to fraction form
    685.33/945.81 = 390.53/x
  3. Step 3: Cross multiply
    685.33x = 945.81 × 390.53
  4. Step 4: Simplify right side
    685.33x = 369,367.18
  5. Step 5: Solve for x
    x = 369,367.18/685.33
  6. Step 6: Final answer
    x = 538.96

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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.