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Finding the Fourth Proportional to 690.30, 1,035.51 and 257.35

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Solution

The fourth proportional to 690.30, 1,035.51 and 257.35 is: 386.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.30 : 1,035.51 = 257.35 : x
  2. Step 2: Convert to fraction form
    690.30/1,035.51 = 257.35/x
  3. Step 3: Cross multiply
    690.30x = 1,035.51 × 257.35
  4. Step 4: Simplify right side
    690.30x = 266,488.50
  5. Step 5: Solve for x
    x = 266,488.50/690.30
  6. Step 6: Final answer
    x = 386.05

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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.