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Finding the Fourth Proportional to 685.26, 945.68 and 390.56

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Solution

The fourth proportional to 685.26, 945.68 and 390.56 is: 538.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.26 : 945.68 = 390.56 : x
  2. Step 2: Convert to fraction form
    685.26/945.68 = 390.56/x
  3. Step 3: Cross multiply
    685.26x = 945.68 × 390.56
  4. Step 4: Simplify right side
    685.26x = 369,338.10
  5. Step 5: Solve for x
    x = 369,338.10/685.26
  6. Step 6: Final answer
    x = 538.98

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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.