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Finding the Fourth Proportional to 140.64, 210.96 and 78.96

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Solution

The fourth proportional to 140.64, 210.96 and 78.96 is: 118.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.64 : 210.96 = 78.96 : x
  2. Step 2: Convert to fraction form
    140.64/210.96 = 78.96/x
  3. Step 3: Cross multiply
    140.64x = 210.96 × 78.96
  4. Step 4: Simplify right side
    140.64x = 16,657.40
  5. Step 5: Solve for x
    x = 16,657.40/140.64
  6. Step 6: Final answer
    x = 118.44

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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.