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Finding the Fourth Proportional to 939.68, 1,409.84 and 420.04

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Solution

The fourth proportional to 939.68, 1,409.84 and 420.04 is: 630.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.68 : 1,409.84 = 420.04 : x
  2. Step 2: Convert to fraction form
    939.68/1,409.84 = 420.04/x
  3. Step 3: Cross multiply
    939.68x = 1,409.84 × 420.04
  4. Step 4: Simplify right side
    939.68x = 592,192.79
  5. Step 5: Solve for x
    x = 592,192.79/939.68
  6. Step 6: Final answer
    x = 630.20

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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.