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Finding the Fourth Proportional to 157.21, 216.94 and 91.72

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Solution

The fourth proportional to 157.21, 216.94 and 91.72 is: 126.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.21 : 216.94 = 91.72 : x
  2. Step 2: Convert to fraction form
    157.21/216.94 = 91.72/x
  3. Step 3: Cross multiply
    157.21x = 216.94 × 91.72
  4. Step 4: Simplify right side
    157.21x = 19,897.74
  5. Step 5: Solve for x
    x = 19,897.74/157.21
  6. Step 6: Final answer
    x = 126.57

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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.