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Finding the Fourth Proportional to 78.06, 116.40 and 77.91

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Solution

The fourth proportional to 78.06, 116.40 and 77.91 is: 116.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.06 : 116.40 = 77.91 : x
  2. Step 2: Convert to fraction form
    78.06/116.40 = 77.91/x
  3. Step 3: Cross multiply
    78.06x = 116.40 × 77.91
  4. Step 4: Simplify right side
    78.06x = 9,068.91
  5. Step 5: Solve for x
    x = 9,068.91/78.06
  6. Step 6: Final answer
    x = 116.17

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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.