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Finding the Fourth Proportional to 78.80, 117.86 and 64.46

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Solution

The fourth proportional to 78.80, 117.86 and 64.46 is: 96.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.80 : 117.86 = 64.46 : x
  2. Step 2: Convert to fraction form
    78.80/117.86 = 64.46/x
  3. Step 3: Cross multiply
    78.80x = 117.86 × 64.46
  4. Step 4: Simplify right side
    78.80x = 7,596.83
  5. Step 5: Solve for x
    x = 7,596.83/78.80
  6. Step 6: Final answer
    x = 96.40

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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.