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Finding the Fourth Proportional to 98.78, 147.93 and 78.50

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Solution

The fourth proportional to 98.78, 147.93 and 78.50 is: 117.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.78 : 147.93 = 78.50 : x
  2. Step 2: Convert to fraction form
    98.78/147.93 = 78.50/x
  3. Step 3: Cross multiply
    98.78x = 147.93 × 78.50
  4. Step 4: Simplify right side
    98.78x = 11,611.77
  5. Step 5: Solve for x
    x = 11,611.77/98.78
  6. Step 6: Final answer
    x = 117.56

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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.