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Finding the Fourth Proportional to 1,428.14, 1,971.05 and 868.78

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Solution

The fourth proportional to 1,428.14, 1,971.05 and 868.78 is: 1,199.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.14 : 1,971.05 = 868.78 : x
  2. Step 2: Convert to fraction form
    1,428.14/1,971.05 = 868.78/x
  3. Step 3: Cross multiply
    1,428.14x = 1,971.05 × 868.78
  4. Step 4: Simplify right side
    1,428.14x = 1,712,415.92
  5. Step 5: Solve for x
    x = 1,712,415.92/1,428.14
  6. Step 6: Final answer
    x = 1,199.06

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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.