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Finding the Fourth Proportional to 144.60, 216.90 and 90.78

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Solution

The fourth proportional to 144.60, 216.90 and 90.78 is: 136.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    144.60 : 216.90 = 90.78 : x
  2. Step 2: Convert to fraction form
    144.60/216.90 = 90.78/x
  3. Step 3: Cross multiply
    144.60x = 216.90 × 90.78
  4. Step 4: Simplify right side
    144.60x = 19,690.18
  5. Step 5: Solve for x
    x = 19,690.18/144.60
  6. Step 6: Final answer
    x = 136.17

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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.