Home / 612.78-845.42-391.72

Finding the Fourth Proportional to 612.78, 845.42 and 391.72

Calculator

Solution

The fourth proportional to 612.78, 845.42 and 391.72 is: 540.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.78 : 845.42 = 391.72 : x
  2. Step 2: Convert to fraction form
    612.78/845.42 = 391.72/x
  3. Step 3: Cross multiply
    612.78x = 845.42 × 391.72
  4. Step 4: Simplify right side
    612.78x = 331,167.92
  5. Step 5: Solve for x
    x = 331,167.92/612.78
  6. Step 6: Final answer
    x = 540.44

Related Problems

Find fourth proportional to 306.39, 422.71 and 195.86
Half scale
Find fourth proportional to 1,225.56, 1,690.84 and 783.44
Double scale
Find fourth proportional to 613.78, 846.80 and 392.72
Similar ratio
Find fourth proportional to 919.17, 1,268.13 and 587.58
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.