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Finding the Fourth Proportional to 986.94, 1,478.09 and 780.12

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Solution

The fourth proportional to 986.94, 1,478.09 and 780.12 is: 1,168.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.94 : 1,478.09 = 780.12 : x
  2. Step 2: Convert to fraction form
    986.94/1,478.09 = 780.12/x
  3. Step 3: Cross multiply
    986.94x = 1,478.09 × 780.12
  4. Step 4: Simplify right side
    986.94x = 1,153,083.67
  5. Step 5: Solve for x
    x = 1,153,083.67/986.94
  6. Step 6: Final answer
    x = 1,168.34

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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.