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Finding the Fourth Proportional to 142.80, 214.24 and 61.72

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Solution

The fourth proportional to 142.80, 214.24 and 61.72 is: 92.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.80 : 214.24 = 61.72 : x
  2. Step 2: Convert to fraction form
    142.80/214.24 = 61.72/x
  3. Step 3: Cross multiply
    142.80x = 214.24 × 61.72
  4. Step 4: Simplify right side
    142.80x = 13,222.89
  5. Step 5: Solve for x
    x = 13,222.89/142.80
  6. Step 6: Final answer
    x = 92.60

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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.