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Finding the Fourth Proportional to 870.42, 1,305.21 and 505.30

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Solution

The fourth proportional to 870.42, 1,305.21 and 505.30 is: 757.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.42 : 1,305.21 = 505.30 : x
  2. Step 2: Convert to fraction form
    870.42/1,305.21 = 505.30/x
  3. Step 3: Cross multiply
    870.42x = 1,305.21 × 505.30
  4. Step 4: Simplify right side
    870.42x = 659,522.61
  5. Step 5: Solve for x
    x = 659,522.61/870.42
  6. Step 6: Final answer
    x = 757.71

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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.