Home / 872.80-1,307.20-439

Finding the Fourth Proportional to 872.80, 1,307.20 and 439

Calculator

Solution

The fourth proportional to 872.80, 1,307.20 and 439 is: 657.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.80 : 1,307.20 = 439 : x
  2. Step 2: Convert to fraction form
    872.80/1,307.20 = 439/x
  3. Step 3: Cross multiply
    872.80x = 1,307.20 × 439
  4. Step 4: Simplify right side
    872.80x = 573,860.80
  5. Step 5: Solve for x
    x = 573,860.80/872.80
  6. Step 6: Final answer
    x = 657.49

Related Problems

Find fourth proportional to 436.40, 653.60 and 219.50
Half scale
Find fourth proportional to 1,745.60, 2,614.40 and 878
Double scale
Find fourth proportional to 873.80, 1,308.70 and 440
Similar ratio
Find fourth proportional to 1,309.20, 1,960.80 and 658.50
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.