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Finding the Fourth Proportional to 142.07, 212.85 and 90.63

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Solution

The fourth proportional to 142.07, 212.85 and 90.63 is: 135.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.07 : 212.85 = 90.63 : x
  2. Step 2: Convert to fraction form
    142.07/212.85 = 90.63/x
  3. Step 3: Cross multiply
    142.07x = 212.85 × 90.63
  4. Step 4: Simplify right side
    142.07x = 19,290.60
  5. Step 5: Solve for x
    x = 19,290.60/142.07
  6. Step 6: Final answer
    x = 135.79

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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.