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Finding the Fourth Proportional to 685.71, 945.99 and 420.26

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Solution

The fourth proportional to 685.71, 945.99 and 420.26 is: 579.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.71 : 945.99 = 420.26 : x
  2. Step 2: Convert to fraction form
    685.71/945.99 = 420.26/x
  3. Step 3: Cross multiply
    685.71x = 945.99 × 420.26
  4. Step 4: Simplify right side
    685.71x = 397,557.03
  5. Step 5: Solve for x
    x = 397,557.03/685.71
  6. Step 6: Final answer
    x = 579.77

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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.