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Finding the Fourth Proportional to 156.70, 216.25 and 91.21

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Solution

The fourth proportional to 156.70, 216.25 and 91.21 is: 125.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.70 : 216.25 = 91.21 : x
  2. Step 2: Convert to fraction form
    156.70/216.25 = 91.21/x
  3. Step 3: Cross multiply
    156.70x = 216.25 × 91.21
  4. Step 4: Simplify right side
    156.70x = 19,724.55
  5. Step 5: Solve for x
    x = 19,724.55/156.70
  6. Step 6: Final answer
    x = 125.87

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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.