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Finding the Fourth Proportional to 430.79, 645.86 and 211.35

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Solution

The fourth proportional to 430.79, 645.86 and 211.35 is: 316.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.79 : 645.86 = 211.35 : x
  2. Step 2: Convert to fraction form
    430.79/645.86 = 211.35/x
  3. Step 3: Cross multiply
    430.79x = 645.86 × 211.35
  4. Step 4: Simplify right side
    430.79x = 136,499.28
  5. Step 5: Solve for x
    x = 136,499.28/430.79
  6. Step 6: Final answer
    x = 316.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.