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Finding the Fourth Proportional to 876.78, 1,315.80 and 511.20

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Solution

The fourth proportional to 876.78, 1,315.80 and 511.20 is: 767.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.78 : 1,315.80 = 511.20 : x
  2. Step 2: Convert to fraction form
    876.78/1,315.80 = 511.20/x
  3. Step 3: Cross multiply
    876.78x = 1,315.80 × 511.20
  4. Step 4: Simplify right side
    876.78x = 672,636.96
  5. Step 5: Solve for x
    x = 672,636.96/876.78
  6. Step 6: Final answer
    x = 767.17

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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.