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Finding the Fourth Proportional to 420, 630 and 131.45

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Solution

The fourth proportional to 420, 630 and 131.45 is: 197.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    420 : 630 = 131.45 : x
  2. Step 2: Convert to fraction form
    420/630 = 131.45/x
  3. Step 3: Cross multiply
    420x = 630 × 131.45
  4. Step 4: Simplify right side
    420x = 82,810.35
  5. Step 5: Solve for x
    x = 82,810.35/420
  6. Step 6: Final answer
    x = 197.17

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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.