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Finding the Fourth Proportional to 1,123.06, 1,685.43 and 430.21

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Solution

The fourth proportional to 1,123.06, 1,685.43 and 430.21 is: 645.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,123.06 : 1,685.43 = 430.21 : x
  2. Step 2: Convert to fraction form
    1,123.06/1,685.43 = 430.21/x
  3. Step 3: Cross multiply
    1,123.06x = 1,685.43 × 430.21
  4. Step 4: Simplify right side
    1,123.06x = 725,088.84
  5. Step 5: Solve for x
    x = 725,088.84/1,123.06
  6. Step 6: Final answer
    x = 645.64

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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.