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Finding the Fourth Proportional to 690.48, 1,036 and 257.76

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Solution

The fourth proportional to 690.48, 1,036 and 257.76 is: 386.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.48 : 1,036 = 257.76 : x
  2. Step 2: Convert to fraction form
    690.48/1,036 = 257.76/x
  3. Step 3: Cross multiply
    690.48x = 1,036 × 257.76
  4. Step 4: Simplify right side
    690.48x = 267,039.36
  5. Step 5: Solve for x
    x = 267,039.36/690.48
  6. Step 6: Final answer
    x = 386.74

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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.