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Finding the Fourth Proportional to 128.94, 193.80 and 98.70

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Solution

The fourth proportional to 128.94, 193.80 and 98.70 is: 148.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.94 : 193.80 = 98.70 : x
  2. Step 2: Convert to fraction form
    128.94/193.80 = 98.70/x
  3. Step 3: Cross multiply
    128.94x = 193.80 × 98.70
  4. Step 4: Simplify right side
    128.94x = 19,128.06
  5. Step 5: Solve for x
    x = 19,128.06/128.94
  6. Step 6: Final answer
    x = 148.35

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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.