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Finding the Fourth Proportional to 47.80, 72.07 and 45.40

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Solution

The fourth proportional to 47.80, 72.07 and 45.40 is: 68.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.80 : 72.07 = 45.40 : x
  2. Step 2: Convert to fraction form
    47.80/72.07 = 45.40/x
  3. Step 3: Cross multiply
    47.80x = 72.07 × 45.40
  4. Step 4: Simplify right side
    47.80x = 3,271.98
  5. Step 5: Solve for x
    x = 3,271.98/47.80
  6. Step 6: Final answer
    x = 68.45

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.