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Finding the Fourth Proportional to 78.81, 117.56 and 74.58

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Solution

The fourth proportional to 78.81, 117.56 and 74.58 is: 111.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 117.56 = 74.58 : x
  2. Step 2: Convert to fraction form
    78.81/117.56 = 74.58/x
  3. Step 3: Cross multiply
    78.81x = 117.56 × 74.58
  4. Step 4: Simplify right side
    78.81x = 8,767.25
  5. Step 5: Solve for x
    x = 8,767.25/78.81
  6. Step 6: Final answer
    x = 111.25

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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.