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Finding the Fourth Proportional to 1,428, 1,970.76 and 807.12

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Solution

The fourth proportional to 1,428, 1,970.76 and 807.12 is: 1,113.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428 : 1,970.76 = 807.12 : x
  2. Step 2: Convert to fraction form
    1,428/1,970.76 = 807.12/x
  3. Step 3: Cross multiply
    1,428x = 1,970.76 × 807.12
  4. Step 4: Simplify right side
    1,428x = 1,590,639.81
  5. Step 5: Solve for x
    x = 1,590,639.81/1,428
  6. Step 6: Final answer
    x = 1,113.89

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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.