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Finding the Fourth Proportional to 69.84, 104.80 and 42.78

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Solution

The fourth proportional to 69.84, 104.80 and 42.78 is: 64.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.84 : 104.80 = 42.78 : x
  2. Step 2: Convert to fraction form
    69.84/104.80 = 42.78/x
  3. Step 3: Cross multiply
    69.84x = 104.80 × 42.78
  4. Step 4: Simplify right side
    69.84x = 4,482.71
  5. Step 5: Solve for x
    x = 4,482.71/69.84
  6. Step 6: Final answer
    x = 64.18

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.