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Finding the Fourth Proportional to 315.20, 472.80 and 98.78

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Solution

The fourth proportional to 315.20, 472.80 and 98.78 is: 148.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    315.20 : 472.80 = 98.78 : x
  2. Step 2: Convert to fraction form
    315.20/472.80 = 98.78/x
  3. Step 3: Cross multiply
    315.20x = 472.80 × 98.78
  4. Step 4: Simplify right side
    315.20x = 46,700.82
  5. Step 5: Solve for x
    x = 46,700.82/315.20
  6. Step 6: Final answer
    x = 148.16

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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.