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Finding the Fourth Proportional to 74.50, 102.78 and 57.00

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Solution

The fourth proportional to 74.50, 102.78 and 57.00 is: 78.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.50 : 102.78 = 57.00 : x
  2. Step 2: Convert to fraction form
    74.50/102.78 = 57.00/x
  3. Step 3: Cross multiply
    74.50x = 102.78 × 57.00
  4. Step 4: Simplify right side
    74.50x = 5,858.85
  5. Step 5: Solve for x
    x = 5,858.85/74.50
  6. Step 6: Final answer
    x = 78.64

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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.