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Finding the Fourth Proportional to 420.40, 630.65 and 156.81

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Solution

The fourth proportional to 420.40, 630.65 and 156.81 is: 235.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.40 : 630.65 = 156.81 : x
  2. Step 2: Convert to fraction form
    420.40/630.65 = 156.81/x
  3. Step 3: Cross multiply
    420.40x = 630.65 × 156.81
  4. Step 4: Simplify right side
    420.40x = 98,892.23
  5. Step 5: Solve for x
    x = 98,892.23/420.40
  6. Step 6: Final answer
    x = 235.23

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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.