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Finding the Fourth Proportional to 78.80, 117.58 and 75.20

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Solution

The fourth proportional to 78.80, 117.58 and 75.20 is: 112.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.80 : 117.58 = 75.20 : x
  2. Step 2: Convert to fraction form
    78.80/117.58 = 75.20/x
  3. Step 3: Cross multiply
    78.80x = 117.58 × 75.20
  4. Step 4: Simplify right side
    78.80x = 8,842.02
  5. Step 5: Solve for x
    x = 8,842.02/78.80
  6. Step 6: Final answer
    x = 112.21

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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.