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Finding the Fourth Proportional to 78.16, 117.06 and 77.32

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Solution

The fourth proportional to 78.16, 117.06 and 77.32 is: 115.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.16 : 117.06 = 77.32 : x
  2. Step 2: Convert to fraction form
    78.16/117.06 = 77.32/x
  3. Step 3: Cross multiply
    78.16x = 117.06 × 77.32
  4. Step 4: Simplify right side
    78.16x = 9,051.08
  5. Step 5: Solve for x
    x = 9,051.08/78.16
  6. Step 6: Final answer
    x = 115.80

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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.