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Finding the Fourth Proportional to 1,438.64, 1,985.28 and 809.12

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Solution

The fourth proportional to 1,438.64, 1,985.28 and 809.12 is: 1,116.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,438.64 : 1,985.28 = 809.12 : x
  2. Step 2: Convert to fraction form
    1,438.64/1,985.28 = 809.12/x
  3. Step 3: Cross multiply
    1,438.64x = 1,985.28 × 809.12
  4. Step 4: Simplify right side
    1,438.64x = 1,606,329.75
  5. Step 5: Solve for x
    x = 1,606,329.75/1,438.64
  6. Step 6: Final answer
    x = 1,116.56

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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.