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Finding the Fourth Proportional to 78.63, 108.29 and 74.71

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Solution

The fourth proportional to 78.63, 108.29 and 74.71 is: 102.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.63 : 108.29 = 74.71 : x
  2. Step 2: Convert to fraction form
    78.63/108.29 = 74.71/x
  3. Step 3: Cross multiply
    78.63x = 108.29 × 74.71
  4. Step 4: Simplify right side
    78.63x = 8,090.35
  5. Step 5: Solve for x
    x = 8,090.35/78.63
  6. Step 6: Final answer
    x = 102.89

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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.