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Finding the Fourth Proportional to 211.65, 291.87 and 156.39

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Solution

The fourth proportional to 211.65, 291.87 and 156.39 is: 215.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.65 : 291.87 = 156.39 : x
  2. Step 2: Convert to fraction form
    211.65/291.87 = 156.39/x
  3. Step 3: Cross multiply
    211.65x = 291.87 × 156.39
  4. Step 4: Simplify right side
    211.65x = 45,645.55
  5. Step 5: Solve for x
    x = 45,645.55/211.65
  6. Step 6: Final answer
    x = 215.67

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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.