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Finding the Fourth Proportional to 128.70, 193.08 and 64.50

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Solution

The fourth proportional to 128.70, 193.08 and 64.50 is: 96.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.70 : 193.08 = 64.50 : x
  2. Step 2: Convert to fraction form
    128.70/193.08 = 64.50/x
  3. Step 3: Cross multiply
    128.70x = 193.08 × 64.50
  4. Step 4: Simplify right side
    128.70x = 12,453.66
  5. Step 5: Solve for x
    x = 12,453.66/128.70
  6. Step 6: Final answer
    x = 96.77

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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.