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Finding the Fourth Proportional to 870.80, 1,306.61 and 438.26

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Solution

The fourth proportional to 870.80, 1,306.61 and 438.26 is: 657.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.80 : 1,306.61 = 438.26 : x
  2. Step 2: Convert to fraction form
    870.80/1,306.61 = 438.26/x
  3. Step 3: Cross multiply
    870.80x = 1,306.61 × 438.26
  4. Step 4: Simplify right side
    870.80x = 572,634.90
  5. Step 5: Solve for x
    x = 572,634.90/870.80
  6. Step 6: Final answer
    x = 657.60

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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.