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Finding the Fourth Proportional to 786.48, 1,085.55 and 491.57

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Solution

The fourth proportional to 786.48, 1,085.55 and 491.57 is: 678.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.48 : 1,085.55 = 491.57 : x
  2. Step 2: Convert to fraction form
    786.48/1,085.55 = 491.57/x
  3. Step 3: Cross multiply
    786.48x = 1,085.55 × 491.57
  4. Step 4: Simplify right side
    786.48x = 533,623.81
  5. Step 5: Solve for x
    x = 533,623.81/786.48
  6. Step 6: Final answer
    x = 678.50

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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.