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Finding the Fourth Proportional to 1,292.78, 1,939.20 and 970.20

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Solution

The fourth proportional to 1,292.78, 1,939.20 and 970.20 is: 1,455.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.78 : 1,939.20 = 970.20 : x
  2. Step 2: Convert to fraction form
    1,292.78/1,939.20 = 970.20/x
  3. Step 3: Cross multiply
    1,292.78x = 1,939.20 × 970.20
  4. Step 4: Simplify right side
    1,292.78x = 1,881,411.84
  5. Step 5: Solve for x
    x = 1,881,411.84/1,292.78
  6. Step 6: Final answer
    x = 1,455.32

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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.