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Finding the Fourth Proportional to 685.40, 1,025.70 and 627.80

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Solution

The fourth proportional to 685.40, 1,025.70 and 627.80 is: 939.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.40 : 1,025.70 = 627.80 : x
  2. Step 2: Convert to fraction form
    685.40/1,025.70 = 627.80/x
  3. Step 3: Cross multiply
    685.40x = 1,025.70 × 627.80
  4. Step 4: Simplify right side
    685.40x = 643,934.46
  5. Step 5: Solve for x
    x = 643,934.46/685.40
  6. Step 6: Final answer
    x = 939.50

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.