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Finding the Fourth Proportional to 1,978.40, 2,972.20 and 1,240.28

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Solution

The fourth proportional to 1,978.40, 2,972.20 and 1,240.28 is: 1,863.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,978.40 : 2,972.20 = 1,240.28 : x
  2. Step 2: Convert to fraction form
    1,978.40/2,972.20 = 1,240.28/x
  3. Step 3: Cross multiply
    1,978.40x = 2,972.20 × 1,240.28
  4. Step 4: Simplify right side
    1,978.40x = 3,686,360.22
  5. Step 5: Solve for x
    x = 3,686,360.22/1,978.40
  6. Step 6: Final answer
    x = 1,863.30

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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.