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Finding the Fourth Proportional to 79.90, 110.21 and 55.31

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Solution

The fourth proportional to 79.90, 110.21 and 55.31 is: 76.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.90 : 110.21 = 55.31 : x
  2. Step 2: Convert to fraction form
    79.90/110.21 = 55.31/x
  3. Step 3: Cross multiply
    79.90x = 110.21 × 55.31
  4. Step 4: Simplify right side
    79.90x = 6,094.89
  5. Step 5: Solve for x
    x = 6,094.89/79.90
  6. Step 6: Final answer
    x = 76.28

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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.