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Finding the Fourth Proportional to 986.21, 1,478.78 and 292.78

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Solution

The fourth proportional to 986.21, 1,478.78 and 292.78 is: 439.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.21 : 1,478.78 = 292.78 : x
  2. Step 2: Convert to fraction form
    986.21/1,478.78 = 292.78/x
  3. Step 3: Cross multiply
    986.21x = 1,478.78 × 292.78
  4. Step 4: Simplify right side
    986.21x = 432,949.81
  5. Step 5: Solve for x
    x = 432,949.81/986.21
  6. Step 6: Final answer
    x = 439.01

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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.