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Finding the Fourth Proportional to 156.21, 215.65 and 121.16

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Solution

The fourth proportional to 156.21, 215.65 and 121.16 is: 167.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    156.21 : 215.65 = 121.16 : x
  2. Step 2: Convert to fraction form
    156.21/215.65 = 121.16/x
  3. Step 3: Cross multiply
    156.21x = 215.65 × 121.16
  4. Step 4: Simplify right side
    156.21x = 26,128.15
  5. Step 5: Solve for x
    x = 26,128.15/156.21
  6. Step 6: Final answer
    x = 167.26

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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.