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Finding the Fourth Proportional to 79.88, 109.98 and 65.28

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Solution

The fourth proportional to 79.88, 109.98 and 65.28 is: 89.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.88 : 109.98 = 65.28 : x
  2. Step 2: Convert to fraction form
    79.88/109.98 = 65.28/x
  3. Step 3: Cross multiply
    79.88x = 109.98 × 65.28
  4. Step 4: Simplify right side
    79.88x = 7,179.49
  5. Step 5: Solve for x
    x = 7,179.49/79.88
  6. Step 6: Final answer
    x = 89.88

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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.