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Finding the Fourth Proportional to 870.32, 1,305.05 and 431.06

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Solution

The fourth proportional to 870.32, 1,305.05 and 431.06 is: 646.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.32 : 1,305.05 = 431.06 : x
  2. Step 2: Convert to fraction form
    870.32/1,305.05 = 431.06/x
  3. Step 3: Cross multiply
    870.32x = 1,305.05 × 431.06
  4. Step 4: Simplify right side
    870.32x = 562,554.85
  5. Step 5: Solve for x
    x = 562,554.85/870.32
  6. Step 6: Final answer
    x = 646.38

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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.