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Finding the Fourth Proportional to 98.58, 147.75 and 85.20

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Solution

The fourth proportional to 98.58, 147.75 and 85.20 is: 127.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.58 : 147.75 = 85.20 : x
  2. Step 2: Convert to fraction form
    98.58/147.75 = 85.20/x
  3. Step 3: Cross multiply
    98.58x = 147.75 × 85.20
  4. Step 4: Simplify right side
    98.58x = 12,588.30
  5. Step 5: Solve for x
    x = 12,588.30/98.58
  6. Step 6: Final answer
    x = 127.70

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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.