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Finding the Fourth Proportional to 431.60, 647.08 and 212.16

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Solution

The fourth proportional to 431.60, 647.08 and 212.16 is: 318.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.60 : 647.08 = 212.16 : x
  2. Step 2: Convert to fraction form
    431.60/647.08 = 212.16/x
  3. Step 3: Cross multiply
    431.60x = 647.08 × 212.16
  4. Step 4: Simplify right side
    431.60x = 137,283.96
  5. Step 5: Solve for x
    x = 137,283.96/431.60
  6. Step 6: Final answer
    x = 318.08

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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.