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Finding the Fourth Proportional to 78.90, 118.42 and 64.62

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Solution

The fourth proportional to 78.90, 118.42 and 64.62 is: 97.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.90 : 118.42 = 64.62 : x
  2. Step 2: Convert to fraction form
    78.90/118.42 = 64.62/x
  3. Step 3: Cross multiply
    78.90x = 118.42 × 64.62
  4. Step 4: Simplify right side
    78.90x = 7,652.93
  5. Step 5: Solve for x
    x = 7,652.93/78.90
  6. Step 6: Final answer
    x = 97.00

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.