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Finding the Fourth Proportional to 98.90, 135.74 and 90.70

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Solution

The fourth proportional to 98.90, 135.74 and 90.70 is: 124.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.90 : 135.74 = 90.70 : x
  2. Step 2: Convert to fraction form
    98.90/135.74 = 90.70/x
  3. Step 3: Cross multiply
    98.90x = 135.74 × 90.70
  4. Step 4: Simplify right side
    98.90x = 12,311.62
  5. Step 5: Solve for x
    x = 12,311.62/98.90
  6. Step 6: Final answer
    x = 124.49

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.