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Finding the Fourth Proportional to 141.78, 212.80 and 90.51

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Solution

The fourth proportional to 141.78, 212.80 and 90.51 is: 135.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    141.78 : 212.80 = 90.51 : x
  2. Step 2: Convert to fraction form
    141.78/212.80 = 90.51/x
  3. Step 3: Cross multiply
    141.78x = 212.80 × 90.51
  4. Step 4: Simplify right side
    141.78x = 19,260.53
  5. Step 5: Solve for x
    x = 19,260.53/141.78
  6. Step 6: Final answer
    x = 135.85

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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.