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Finding the Fourth Proportional to 685.35, 945.72 and 386.55

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Solution

The fourth proportional to 685.35, 945.72 and 386.55 is: 533.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.35 : 945.72 = 386.55 : x
  2. Step 2: Convert to fraction form
    685.35/945.72 = 386.55/x
  3. Step 3: Cross multiply
    685.35x = 945.72 × 386.55
  4. Step 4: Simplify right side
    685.35x = 365,568.07
  5. Step 5: Solve for x
    x = 365,568.07/685.35
  6. Step 6: Final answer
    x = 533.40

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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.