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Finding the Fourth Proportional to 156.80, 215.90 and 142.15

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Solution

The fourth proportional to 156.80, 215.90 and 142.15 is: 195.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.80 : 215.90 = 142.15 : x
  2. Step 2: Convert to fraction form
    156.80/215.90 = 142.15/x
  3. Step 3: Cross multiply
    156.80x = 215.90 × 142.15
  4. Step 4: Simplify right side
    156.80x = 30,689.11
  5. Step 5: Solve for x
    x = 30,689.11/156.80
  6. Step 6: Final answer
    x = 195.73

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.