Home / 872.72-1,309.31-287.81

Finding the Fourth Proportional to 872.72, 1,309.31 and 287.81

Calculator

Solution

The fourth proportional to 872.72, 1,309.31 and 287.81 is: 431.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.72 : 1,309.31 = 287.81 : x
  2. Step 2: Convert to fraction form
    872.72/1,309.31 = 287.81/x
  3. Step 3: Cross multiply
    872.72x = 1,309.31 × 287.81
  4. Step 4: Simplify right side
    872.72x = 376,831.07
  5. Step 5: Solve for x
    x = 376,831.07/872.72
  6. Step 6: Final answer
    x = 431.79

Related Problems

Find fourth proportional to 436.36, 654.65 and 143.91
Half scale
Find fourth proportional to 1,745.44, 2,618.61 and 575.62
Double scale
Find fourth proportional to 873.72, 1,310.81 and 288.81
Similar ratio
Find fourth proportional to 1,309.08, 1,963.96 and 431.72
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.