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Finding the Fourth Proportional to 211.65, 291.65 and 156.30

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Solution

The fourth proportional to 211.65, 291.65 and 156.30 is: 215.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.65 : 291.65 = 156.30 : x
  2. Step 2: Convert to fraction form
    211.65/291.65 = 156.30/x
  3. Step 3: Cross multiply
    211.65x = 291.65 × 156.30
  4. Step 4: Simplify right side
    211.65x = 45,584.11
  5. Step 5: Solve for x
    x = 45,584.11/211.65
  6. Step 6: Final answer
    x = 215.37

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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.