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Finding the Fourth Proportional to 1,428.70, 2,143.86 and 780.16

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Solution

The fourth proportional to 1,428.70, 2,143.86 and 780.16 is: 1,170.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.70 : 2,143.86 = 780.16 : x
  2. Step 2: Convert to fraction form
    1,428.70/2,143.86 = 780.16/x
  3. Step 3: Cross multiply
    1,428.70x = 2,143.86 × 780.16
  4. Step 4: Simplify right side
    1,428.70x = 1,672,553.82
  5. Step 5: Solve for x
    x = 1,672,553.82/1,428.70
  6. Step 6: Final answer
    x = 1,170.68

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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.