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Finding the Fourth Proportional to 805.69, 1,205.60 and 688.64

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Solution

The fourth proportional to 805.69, 1,205.60 and 688.64 is: 1,030.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.69 : 1,205.60 = 688.64 : x
  2. Step 2: Convert to fraction form
    805.69/1,205.60 = 688.64/x
  3. Step 3: Cross multiply
    805.69x = 1,205.60 × 688.64
  4. Step 4: Simplify right side
    805.69x = 830,223.95
  5. Step 5: Solve for x
    x = 830,223.95/805.69
  6. Step 6: Final answer
    x = 1,030.45

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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.