Home / 1,280.72-1,921.79-1,187.78

Finding the Fourth Proportional to 1,280.72, 1,921.79 and 1,187.78

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Solution

The fourth proportional to 1,280.72, 1,921.79 and 1,187.78 is: 1,782.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.72 : 1,921.79 = 1,187.78 : x
  2. Step 2: Convert to fraction form
    1,280.72/1,921.79 = 1,187.78/x
  3. Step 3: Cross multiply
    1,280.72x = 1,921.79 × 1,187.78
  4. Step 4: Simplify right side
    1,280.72x = 2,282,657.09
  5. Step 5: Solve for x
    x = 2,282,657.09/1,280.72
  6. Step 6: Final answer
    x = 1,782.32

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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.