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Finding the Fourth Proportional to 78.79, 108.76 and 49.70

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Solution

The fourth proportional to 78.79, 108.76 and 49.70 is: 68.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.79 : 108.76 = 49.70 : x
  2. Step 2: Convert to fraction form
    78.79/108.76 = 49.70/x
  3. Step 3: Cross multiply
    78.79x = 108.76 × 49.70
  4. Step 4: Simplify right side
    78.79x = 5,405.25
  5. Step 5: Solve for x
    x = 5,405.25/78.79
  6. Step 6: Final answer
    x = 68.60

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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.