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Finding the Fourth Proportional to 71.70, 98.90 and 45.78

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Solution

The fourth proportional to 71.70, 98.90 and 45.78 is: 63.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.70 : 98.90 = 45.78 : x
  2. Step 2: Convert to fraction form
    71.70/98.90 = 45.78/x
  3. Step 3: Cross multiply
    71.70x = 98.90 × 45.78
  4. Step 4: Simplify right side
    71.70x = 4,527.64
  5. Step 5: Solve for x
    x = 4,527.64/71.70
  6. Step 6: Final answer
    x = 63.15

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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.