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Finding the Fourth Proportional to 156.42, 215.78 and 98.20

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Solution

The fourth proportional to 156.42, 215.78 and 98.20 is: 135.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.42 : 215.78 = 98.20 : x
  2. Step 2: Convert to fraction form
    156.42/215.78 = 98.20/x
  3. Step 3: Cross multiply
    156.42x = 215.78 × 98.20
  4. Step 4: Simplify right side
    156.42x = 21,189.60
  5. Step 5: Solve for x
    x = 21,189.60/156.42
  6. Step 6: Final answer
    x = 135.47

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.