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Finding the Fourth Proportional to 98.90, 147.62 and 86.75

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Solution

The fourth proportional to 98.90, 147.62 and 86.75 is: 129.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.90 : 147.62 = 86.75 : x
  2. Step 2: Convert to fraction form
    98.90/147.62 = 86.75/x
  3. Step 3: Cross multiply
    98.90x = 147.62 × 86.75
  4. Step 4: Simplify right side
    98.90x = 12,806.04
  5. Step 5: Solve for x
    x = 12,806.04/98.90
  6. Step 6: Final answer
    x = 129.48

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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.