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Finding the Fourth Proportional to 86.90, 120.04 and 74.66

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Solution

The fourth proportional to 86.90, 120.04 and 74.66 is: 103.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.90 : 120.04 = 74.66 : x
  2. Step 2: Convert to fraction form
    86.90/120.04 = 74.66/x
  3. Step 3: Cross multiply
    86.90x = 120.04 × 74.66
  4. Step 4: Simplify right side
    86.90x = 8,962.19
  5. Step 5: Solve for x
    x = 8,962.19/86.90
  6. Step 6: Final answer
    x = 103.13

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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.