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Finding the Fourth Proportional to 98.71, 147.81 and 78.45

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Solution

The fourth proportional to 98.71, 147.81 and 78.45 is: 117.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.71 : 147.81 = 78.45 : x
  2. Step 2: Convert to fraction form
    98.71/147.81 = 78.45/x
  3. Step 3: Cross multiply
    98.71x = 147.81 × 78.45
  4. Step 4: Simplify right side
    98.71x = 11,595.69
  5. Step 5: Solve for x
    x = 11,595.69/98.71
  6. Step 6: Final answer
    x = 117.47

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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.