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Finding the Fourth Proportional to 690.40, 1,035.53 and 279.57

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Solution

The fourth proportional to 690.40, 1,035.53 and 279.57 is: 419.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 1,035.53 = 279.57 : x
  2. Step 2: Convert to fraction form
    690.40/1,035.53 = 279.57/x
  3. Step 3: Cross multiply
    690.40x = 1,035.53 × 279.57
  4. Step 4: Simplify right side
    690.40x = 289,503.12
  5. Step 5: Solve for x
    x = 289,503.12/690.40
  6. Step 6: Final answer
    x = 419.33

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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.