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Finding the Fourth Proportional to 810.81, 1,215.41 and 425.25

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Solution

The fourth proportional to 810.81, 1,215.41 and 425.25 is: 637.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.81 : 1,215.41 = 425.25 : x
  2. Step 2: Convert to fraction form
    810.81/1,215.41 = 425.25/x
  3. Step 3: Cross multiply
    810.81x = 1,215.41 × 425.25
  4. Step 4: Simplify right side
    810.81x = 516,850.98
  5. Step 5: Solve for x
    x = 516,850.98/810.81
  6. Step 6: Final answer
    x = 637.45

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1.5x scale

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.