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Finding the Fourth Proportional to 986.06, 1,478.56 and 438.40

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Solution

The fourth proportional to 986.06, 1,478.56 and 438.40 is: 657.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.06 : 1,478.56 = 438.40 : x
  2. Step 2: Convert to fraction form
    986.06/1,478.56 = 438.40/x
  3. Step 3: Cross multiply
    986.06x = 1,478.56 × 438.40
  4. Step 4: Simplify right side
    986.06x = 648,200.70
  5. Step 5: Solve for x
    x = 648,200.70/986.06
  6. Step 6: Final answer
    x = 657.36

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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.