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Finding the Fourth Proportional to 1,378.88, 2,068.48 and 685.76

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Solution

The fourth proportional to 1,378.88, 2,068.48 and 685.76 is: 1,028.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.88 : 2,068.48 = 685.76 : x
  2. Step 2: Convert to fraction form
    1,378.88/2,068.48 = 685.76/x
  3. Step 3: Cross multiply
    1,378.88x = 2,068.48 × 685.76
  4. Step 4: Simplify right side
    1,378.88x = 1,418,480.84
  5. Step 5: Solve for x
    x = 1,418,480.84/1,378.88
  6. Step 6: Final answer
    x = 1,028.72

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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.