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Finding the Fourth Proportional to 420.36, 630.69 and 258.15

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Solution

The fourth proportional to 420.36, 630.69 and 258.15 is: 387.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.36 : 630.69 = 258.15 : x
  2. Step 2: Convert to fraction form
    420.36/630.69 = 258.15/x
  3. Step 3: Cross multiply
    420.36x = 630.69 × 258.15
  4. Step 4: Simplify right side
    420.36x = 162,814.02
  5. Step 5: Solve for x
    x = 162,814.02/420.36
  6. Step 6: Final answer
    x = 387.32

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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.