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Finding the Fourth Proportional to 876.63, 1,312.21 and 645.78

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Solution

The fourth proportional to 876.63, 1,312.21 and 645.78 is: 966.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.63 : 1,312.21 = 645.78 : x
  2. Step 2: Convert to fraction form
    876.63/1,312.21 = 645.78/x
  3. Step 3: Cross multiply
    876.63x = 1,312.21 × 645.78
  4. Step 4: Simplify right side
    876.63x = 847,395.74
  5. Step 5: Solve for x
    x = 847,395.74/876.63
  6. Step 6: Final answer
    x = 966.65

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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.