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Finding the Fourth Proportional to 98.39, 148.32 and 91.78

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Solution

The fourth proportional to 98.39, 148.32 and 91.78 is: 138.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.39 : 148.32 = 91.78 : x
  2. Step 2: Convert to fraction form
    98.39/148.32 = 91.78/x
  3. Step 3: Cross multiply
    98.39x = 148.32 × 91.78
  4. Step 4: Simplify right side
    98.39x = 13,612.81
  5. Step 5: Solve for x
    x = 13,612.81/98.39
  6. Step 6: Final answer
    x = 138.36

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.