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Finding the Fourth Proportional to 870.31, 1,303.83 and 431.05

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Solution

The fourth proportional to 870.31, 1,303.83 and 431.05 is: 645.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.31 : 1,303.83 = 431.05 : x
  2. Step 2: Convert to fraction form
    870.31/1,303.83 = 431.05/x
  3. Step 3: Cross multiply
    870.31x = 1,303.83 × 431.05
  4. Step 4: Simplify right side
    870.31x = 562,015.92
  5. Step 5: Solve for x
    x = 562,015.92/870.31
  6. Step 6: Final answer
    x = 645.77

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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.