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Finding the Fourth Proportional to 208.40, 312.64 and 105.60

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Solution

The fourth proportional to 208.40, 312.64 and 105.60 is: 158.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.40 : 312.64 = 105.60 : x
  2. Step 2: Convert to fraction form
    208.40/312.64 = 105.60/x
  3. Step 3: Cross multiply
    208.40x = 312.64 × 105.60
  4. Step 4: Simplify right side
    208.40x = 33,014.78
  5. Step 5: Solve for x
    x = 33,014.78/208.40
  6. Step 6: Final answer
    x = 158.42

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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.