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Finding the Fourth Proportional to 811.64, 1,120 and 480

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Solution

The fourth proportional to 811.64, 1,120 and 480 is: 662.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.64 : 1,120 = 480 : x
  2. Step 2: Convert to fraction form
    811.64/1,120 = 480/x
  3. Step 3: Cross multiply
    811.64x = 1,120 × 480
  4. Step 4: Simplify right side
    811.64x = 537,600
  5. Step 5: Solve for x
    x = 537,600/811.64
  6. Step 6: Final answer
    x = 662.36

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.