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Finding the Fourth Proportional to 100.35, 149.79 and 85.80

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Solution

The fourth proportional to 100.35, 149.79 and 85.80 is: 128.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.35 : 149.79 = 85.80 : x
  2. Step 2: Convert to fraction form
    100.35/149.79 = 85.80/x
  3. Step 3: Cross multiply
    100.35x = 149.79 × 85.80
  4. Step 4: Simplify right side
    100.35x = 12,851.98
  5. Step 5: Solve for x
    x = 12,851.98/100.35
  6. Step 6: Final answer
    x = 128.07

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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.