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Finding the Fourth Proportional to 685.55, 945.79 and 405.59

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Solution

The fourth proportional to 685.55, 945.79 and 405.59 is: 559.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.55 : 945.79 = 405.59 : x
  2. Step 2: Convert to fraction form
    685.55/945.79 = 405.59/x
  3. Step 3: Cross multiply
    685.55x = 945.79 × 405.59
  4. Step 4: Simplify right side
    685.55x = 383,597.22
  5. Step 5: Solve for x
    x = 383,597.22/685.55
  6. Step 6: Final answer
    x = 559.54

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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.