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Finding the Fourth Proportional to 685.68, 946.28 and 390.98

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Solution

The fourth proportional to 685.68, 946.28 and 390.98 is: 539.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.68 : 946.28 = 390.98 : x
  2. Step 2: Convert to fraction form
    685.68/946.28 = 390.98/x
  3. Step 3: Cross multiply
    685.68x = 946.28 × 390.98
  4. Step 4: Simplify right side
    685.68x = 369,976.55
  5. Step 5: Solve for x
    x = 369,976.55/685.68
  6. Step 6: Final answer
    x = 539.58

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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.