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Finding the Fourth Proportional to 1,380.76, 1,905.28 and 821.24

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Solution

The fourth proportional to 1,380.76, 1,905.28 and 821.24 is: 1,133.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.76 : 1,905.28 = 821.24 : x
  2. Step 2: Convert to fraction form
    1,380.76/1,905.28 = 821.24/x
  3. Step 3: Cross multiply
    1,380.76x = 1,905.28 × 821.24
  4. Step 4: Simplify right side
    1,380.76x = 1,564,692.15
  5. Step 5: Solve for x
    x = 1,564,692.15/1,380.76
  6. Step 6: Final answer
    x = 1,133.21

Related Problems

Find fourth proportional to 690.38, 952.64 and 410.62
Half scale
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Double scale
Find fourth proportional to 1,381.76, 1,906.66 and 822.24
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1.5x scale

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.