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Finding the Fourth Proportional to 1,918.12, 2,877.78 and 685.50

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Solution

The fourth proportional to 1,918.12, 2,877.78 and 685.50 is: 1,028.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,918.12 : 2,877.78 = 685.50 : x
  2. Step 2: Convert to fraction form
    1,918.12/2,877.78 = 685.50/x
  3. Step 3: Cross multiply
    1,918.12x = 2,877.78 × 685.50
  4. Step 4: Simplify right side
    1,918.12x = 1,972,720.76
  5. Step 5: Solve for x
    x = 1,972,720.76/1,918.12
  6. Step 6: Final answer
    x = 1,028.47

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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.