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Finding the Fourth Proportional to 870.92, 1,304.40 and 438.20

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Solution

The fourth proportional to 870.92, 1,304.40 and 438.20 is: 656.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.92 : 1,304.40 = 438.20 : x
  2. Step 2: Convert to fraction form
    870.92/1,304.40 = 438.20/x
  3. Step 3: Cross multiply
    870.92x = 1,304.40 × 438.20
  4. Step 4: Simplify right side
    870.92x = 571,588.08
  5. Step 5: Solve for x
    x = 571,588.08/870.92
  6. Step 6: Final answer
    x = 656.30

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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.