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Finding the Fourth Proportional to 685.95, 946.35 and 420.31

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Solution

The fourth proportional to 685.95, 946.35 and 420.31 is: 579.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.95 : 946.35 = 420.31 : x
  2. Step 2: Convert to fraction form
    685.95/946.35 = 420.31/x
  3. Step 3: Cross multiply
    685.95x = 946.35 × 420.31
  4. Step 4: Simplify right side
    685.95x = 397,760.37
  5. Step 5: Solve for x
    x = 397,760.37/685.95
  6. Step 6: Final answer
    x = 579.87

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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.