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Finding the Fourth Proportional to 78.81, 108.74 and 45.61

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Solution

The fourth proportional to 78.81, 108.74 and 45.61 is: 62.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 108.74 = 45.61 : x
  2. Step 2: Convert to fraction form
    78.81/108.74 = 45.61/x
  3. Step 3: Cross multiply
    78.81x = 108.74 × 45.61
  4. Step 4: Simplify right side
    78.81x = 4,959.40
  5. Step 5: Solve for x
    x = 4,959.40/78.81
  6. Step 6: Final answer
    x = 62.93

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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.