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Finding the Fourth Proportional to 807.30, 1,210.74 and 390.42

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Solution

The fourth proportional to 807.30, 1,210.74 and 390.42 is: 585.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.30 : 1,210.74 = 390.42 : x
  2. Step 2: Convert to fraction form
    807.30/1,210.74 = 390.42/x
  3. Step 3: Cross multiply
    807.30x = 1,210.74 × 390.42
  4. Step 4: Simplify right side
    807.30x = 472,697.11
  5. Step 5: Solve for x
    x = 472,697.11/807.30
  6. Step 6: Final answer
    x = 585.53

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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.