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Finding the Fourth Proportional to 78.72, 108.62 and 70.01

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Solution

The fourth proportional to 78.72, 108.62 and 70.01 is: 96.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.72 : 108.62 = 70.01 : x
  2. Step 2: Convert to fraction form
    78.72/108.62 = 70.01/x
  3. Step 3: Cross multiply
    78.72x = 108.62 × 70.01
  4. Step 4: Simplify right side
    78.72x = 7,604.14
  5. Step 5: Solve for x
    x = 7,604.14/78.72
  6. Step 6: Final answer
    x = 96.60

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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.