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Finding the Fourth Proportional to 77.65, 107.15 and 72.07

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Solution

The fourth proportional to 77.65, 107.15 and 72.07 is: 99.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.65 : 107.15 = 72.07 : x
  2. Step 2: Convert to fraction form
    77.65/107.15 = 72.07/x
  3. Step 3: Cross multiply
    77.65x = 107.15 × 72.07
  4. Step 4: Simplify right side
    77.65x = 7,722.30
  5. Step 5: Solve for x
    x = 7,722.30/77.65
  6. Step 6: Final answer
    x = 99.45

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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.