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Finding the Fourth Proportional to 71.50, 98.70 and 50.78

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Solution

The fourth proportional to 71.50, 98.70 and 50.78 is: 70.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.50 : 98.70 = 50.78 : x
  2. Step 2: Convert to fraction form
    71.50/98.70 = 50.78/x
  3. Step 3: Cross multiply
    71.50x = 98.70 × 50.78
  4. Step 4: Simplify right side
    71.50x = 5,011.99
  5. Step 5: Solve for x
    x = 5,011.99/71.50
  6. Step 6: Final answer
    x = 70.10

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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.