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Finding the Fourth Proportional to 685.35, 1,030.05 and 678.06

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Solution

The fourth proportional to 685.35, 1,030.05 and 678.06 is: 1,019.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.35 : 1,030.05 = 678.06 : x
  2. Step 2: Convert to fraction form
    685.35/1,030.05 = 678.06/x
  3. Step 3: Cross multiply
    685.35x = 1,030.05 × 678.06
  4. Step 4: Simplify right side
    685.35x = 698,435.70
  5. Step 5: Solve for x
    x = 698,435.70/685.35
  6. Step 6: Final answer
    x = 1,019.09

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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.