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Finding the Fourth Proportional to 70.90, 97.80 and 55.30

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Solution

The fourth proportional to 70.90, 97.80 and 55.30 is: 76.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.90 : 97.80 = 55.30 : x
  2. Step 2: Convert to fraction form
    70.90/97.80 = 55.30/x
  3. Step 3: Cross multiply
    70.90x = 97.80 × 55.30
  4. Step 4: Simplify right side
    70.90x = 5,408.34
  5. Step 5: Solve for x
    x = 5,408.34/70.90
  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.