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Finding the Fourth Proportional to 1,223.76, 1,688.75 and 664.21

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Solution

The fourth proportional to 1,223.76, 1,688.75 and 664.21 is: 916.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.76 : 1,688.75 = 664.21 : x
  2. Step 2: Convert to fraction form
    1,223.76/1,688.75 = 664.21/x
  3. Step 3: Cross multiply
    1,223.76x = 1,688.75 × 664.21
  4. Step 4: Simplify right side
    1,223.76x = 1,121,684.64
  5. Step 5: Solve for x
    x = 1,121,684.64/1,223.76
  6. Step 6: Final answer
    x = 916.59

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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.