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Finding the Fourth Proportional to 100.77, 139.09 and 65.74

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Solution

The fourth proportional to 100.77, 139.09 and 65.74 is: 90.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.77 : 139.09 = 65.74 : x
  2. Step 2: Convert to fraction form
    100.77/139.09 = 65.74/x
  3. Step 3: Cross multiply
    100.77x = 139.09 × 65.74
  4. Step 4: Simplify right side
    100.77x = 9,144.18
  5. Step 5: Solve for x
    x = 9,144.18/100.77
  6. Step 6: Final answer
    x = 90.74

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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.