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Finding the Fourth Proportional to 156.20, 215.52 and 90.69

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Solution

The fourth proportional to 156.20, 215.52 and 90.69 is: 125.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.20 : 215.52 = 90.69 : x
  2. Step 2: Convert to fraction form
    156.20/215.52 = 90.69/x
  3. Step 3: Cross multiply
    156.20x = 215.52 × 90.69
  4. Step 4: Simplify right side
    156.20x = 19,545.51
  5. Step 5: Solve for x
    x = 19,545.51/156.20
  6. Step 6: Final answer
    x = 125.13

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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.