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Finding the Fourth Proportional to 421.12, 580.66 and 316.40

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Solution

The fourth proportional to 421.12, 580.66 and 316.40 is: 436.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.12 : 580.66 = 316.40 : x
  2. Step 2: Convert to fraction form
    421.12/580.66 = 316.40/x
  3. Step 3: Cross multiply
    421.12x = 580.66 × 316.40
  4. Step 4: Simplify right side
    421.12x = 183,720.82
  5. Step 5: Solve for x
    x = 183,720.82/421.12
  6. Step 6: Final answer
    x = 436.27

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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.