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Finding the Fourth Proportional to 762.40, 1,140.72 and 722.80

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Solution

The fourth proportional to 762.40, 1,140.72 and 722.80 is: 1,081.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    762.40 : 1,140.72 = 722.80 : x
  2. Step 2: Convert to fraction form
    762.40/1,140.72 = 722.80/x
  3. Step 3: Cross multiply
    762.40x = 1,140.72 × 722.80
  4. Step 4: Simplify right side
    762.40x = 824,512.42
  5. Step 5: Solve for x
    x = 824,512.42/762.40
  6. Step 6: Final answer
    x = 1,081.47

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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.