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Finding the Fourth Proportional to 810.75, 1,215.59 and 400.15

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Solution

The fourth proportional to 810.75, 1,215.59 and 400.15 is: 599.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.75 : 1,215.59 = 400.15 : x
  2. Step 2: Convert to fraction form
    810.75/1,215.59 = 400.15/x
  3. Step 3: Cross multiply
    810.75x = 1,215.59 × 400.15
  4. Step 4: Simplify right side
    810.75x = 486,416.34
  5. Step 5: Solve for x
    x = 486,416.34/810.75
  6. Step 6: Final answer
    x = 599.96

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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.