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Finding the Fourth Proportional to 685.95, 946.61 and 391.23

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Solution

The fourth proportional to 685.95, 946.61 and 391.23 is: 539.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.95 : 946.61 = 391.23 : x
  2. Step 2: Convert to fraction form
    685.95/946.61 = 391.23/x
  3. Step 3: Cross multiply
    685.95x = 946.61 × 391.23
  4. Step 4: Simplify right side
    685.95x = 370,339.86
  5. Step 5: Solve for x
    x = 370,339.86/685.95
  6. Step 6: Final answer
    x = 539.90

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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.