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Finding the Fourth Proportional to 685.22, 945.55 and 405.43

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Solution

The fourth proportional to 685.22, 945.55 and 405.43 is: 559.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.22 : 945.55 = 405.43 : x
  2. Step 2: Convert to fraction form
    685.22/945.55 = 405.43/x
  3. Step 3: Cross multiply
    685.22x = 945.55 × 405.43
  4. Step 4: Simplify right side
    685.22x = 383,354.34
  5. Step 5: Solve for x
    x = 383,354.34/685.22
  6. Step 6: Final answer
    x = 559.46

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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.