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Finding the Fourth Proportional to 718.08, 990.40 and 485.16

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Solution

The fourth proportional to 718.08, 990.40 and 485.16 is: 669.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.08 : 990.40 = 485.16 : x
  2. Step 2: Convert to fraction form
    718.08/990.40 = 485.16/x
  3. Step 3: Cross multiply
    718.08x = 990.40 × 485.16
  4. Step 4: Simplify right side
    718.08x = 480,502.46
  5. Step 5: Solve for x
    x = 480,502.46/718.08
  6. Step 6: Final answer
    x = 669.15

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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.