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Finding the Fourth Proportional to 690.43, 1,036.15 and 430.81

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Solution

The fourth proportional to 690.43, 1,036.15 and 430.81 is: 646.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.43 : 1,036.15 = 430.81 : x
  2. Step 2: Convert to fraction form
    690.43/1,036.15 = 430.81/x
  3. Step 3: Cross multiply
    690.43x = 1,036.15 × 430.81
  4. Step 4: Simplify right side
    690.43x = 446,383.78
  5. Step 5: Solve for x
    x = 446,383.78/690.43
  6. Step 6: Final answer
    x = 646.53

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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.