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Finding the Fourth Proportional to 690.74, 1,036.68 and 485.72

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Solution

The fourth proportional to 690.74, 1,036.68 and 485.72 is: 728.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.74 : 1,036.68 = 485.72 : x
  2. Step 2: Convert to fraction form
    690.74/1,036.68 = 485.72/x
  3. Step 3: Cross multiply
    690.74x = 1,036.68 × 485.72
  4. Step 4: Simplify right side
    690.74x = 503,536.21
  5. Step 5: Solve for x
    x = 503,536.21/690.74
  6. Step 6: Final answer
    x = 728.98

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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.