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Finding the Fourth Proportional to 1,230.90, 1,699.40 and 915.80

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Solution

The fourth proportional to 1,230.90, 1,699.40 and 915.80 is: 1,264.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,230.90 : 1,699.40 = 915.80 : x
  2. Step 2: Convert to fraction form
    1,230.90/1,699.40 = 915.80/x
  3. Step 3: Cross multiply
    1,230.90x = 1,699.40 × 915.80
  4. Step 4: Simplify right side
    1,230.90x = 1,556,310.52
  5. Step 5: Solve for x
    x = 1,556,310.52/1,230.90
  6. Step 6: Final answer
    x = 1,264.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.