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Finding the Fourth Proportional to 215.09, 322.61 and 78.11

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Solution

The fourth proportional to 215.09, 322.61 and 78.11 is: 117.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.09 : 322.61 = 78.11 : x
  2. Step 2: Convert to fraction form
    215.09/322.61 = 78.11/x
  3. Step 3: Cross multiply
    215.09x = 322.61 × 78.11
  4. Step 4: Simplify right side
    215.09x = 25,197.65
  5. Step 5: Solve for x
    x = 25,197.65/215.09
  6. Step 6: Final answer
    x = 117.15

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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.