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Finding the Fourth Proportional to 78.42, 117.03 and 71.13

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Solution

The fourth proportional to 78.42, 117.03 and 71.13 is: 106.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.42 : 117.03 = 71.13 : x
  2. Step 2: Convert to fraction form
    78.42/117.03 = 71.13/x
  3. Step 3: Cross multiply
    78.42x = 117.03 × 71.13
  4. Step 4: Simplify right side
    78.42x = 8,324.34
  5. Step 5: Solve for x
    x = 8,324.34/78.42
  6. Step 6: Final answer
    x = 106.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.