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Finding the Fourth Proportional to 1,315.86, 1,816.06 and 785

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Solution

The fourth proportional to 1,315.86, 1,816.06 and 785 is: 1,083.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,315.86 : 1,816.06 = 785 : x
  2. Step 2: Convert to fraction form
    1,315.86/1,816.06 = 785/x
  3. Step 3: Cross multiply
    1,315.86x = 1,816.06 × 785
  4. Step 4: Simplify right side
    1,315.86x = 1,425,607.10
  5. Step 5: Solve for x
    x = 1,425,607.10/1,315.86
  6. Step 6: Final answer
    x = 1,083.40

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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.