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Finding the Fourth Proportional to 685.40, 945.76 and 419.80

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Solution

The fourth proportional to 685.40, 945.76 and 419.80 is: 579.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.40 : 945.76 = 419.80 : x
  2. Step 2: Convert to fraction form
    685.40/945.76 = 419.80/x
  3. Step 3: Cross multiply
    685.40x = 945.76 × 419.80
  4. Step 4: Simplify right side
    685.40x = 397,030.05
  5. Step 5: Solve for x
    x = 397,030.05/685.40
  6. Step 6: Final answer
    x = 579.27

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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.