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Finding the Fourth Proportional to 2,915, 4,021.56 and 1,920.80

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Solution

The fourth proportional to 2,915, 4,021.56 and 1,920.80 is: 2,649.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,915 : 4,021.56 = 1,920.80 : x
  2. Step 2: Convert to fraction form
    2,915/4,021.56 = 1,920.80/x
  3. Step 3: Cross multiply
    2,915x = 4,021.56 × 1,920.80
  4. Step 4: Simplify right side
    2,915x = 7,724,612.45
  5. Step 5: Solve for x
    x = 7,724,612.45/2,915
  6. Step 6: Final answer
    x = 2,649.95

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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.