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Finding the Fourth Proportional to 710.55, 1,065.21 and 421.38

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Solution

The fourth proportional to 710.55, 1,065.21 and 421.38 is: 631.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    710.55 : 1,065.21 = 421.38 : x
  2. Step 2: Convert to fraction form
    710.55/1,065.21 = 421.38/x
  3. Step 3: Cross multiply
    710.55x = 1,065.21 × 421.38
  4. Step 4: Simplify right side
    710.55x = 448,858.19
  5. Step 5: Solve for x
    x = 448,858.19/710.55
  6. Step 6: Final answer
    x = 631.71

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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.