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Finding the Fourth Proportional to 98.75, 147.36 and 85.79

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Solution

The fourth proportional to 98.75, 147.36 and 85.79 is: 128.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.75 : 147.36 = 85.79 : x
  2. Step 2: Convert to fraction form
    98.75/147.36 = 85.79/x
  3. Step 3: Cross multiply
    98.75x = 147.36 × 85.79
  4. Step 4: Simplify right side
    98.75x = 12,642.01
  5. Step 5: Solve for x
    x = 12,642.01/98.75
  6. Step 6: Final answer
    x = 128.02

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.