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Finding the Fourth Proportional to 876.32, 1,314.80 and 420

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Solution

The fourth proportional to 876.32, 1,314.80 and 420 is: 630.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.32 : 1,314.80 = 420 : x
  2. Step 2: Convert to fraction form
    876.32/1,314.80 = 420/x
  3. Step 3: Cross multiply
    876.32x = 1,314.80 × 420
  4. Step 4: Simplify right side
    876.32x = 552,216
  5. Step 5: Solve for x
    x = 552,216/876.32
  6. Step 6: Final answer
    x = 630.15

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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.