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Finding the Fourth Proportional to 78.81, 117.54 and 74.76

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Solution

The fourth proportional to 78.81, 117.54 and 74.76 is: 111.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 117.54 = 74.76 : x
  2. Step 2: Convert to fraction form
    78.81/117.54 = 74.76/x
  3. Step 3: Cross multiply
    78.81x = 117.54 × 74.76
  4. Step 4: Simplify right side
    78.81x = 8,787.29
  5. Step 5: Solve for x
    x = 8,787.29/78.81
  6. Step 6: Final answer
    x = 111.50

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.