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Finding the Fourth Proportional to 97.80, 146.70 and 91.80

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Solution

The fourth proportional to 97.80, 146.70 and 91.80 is: 137.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    97.80 : 146.70 = 91.80 : x
  2. Step 2: Convert to fraction form
    97.80/146.70 = 91.80/x
  3. Step 3: Cross multiply
    97.80x = 146.70 × 91.80
  4. Step 4: Simplify right side
    97.80x = 13,467.06
  5. Step 5: Solve for x
    x = 13,467.06/97.80
  6. Step 6: Final answer
    x = 137.70

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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.