Home / 664.79-917.30-399.15

Finding the Fourth Proportional to 664.79, 917.30 and 399.15

Calculator

Solution

The fourth proportional to 664.79, 917.30 and 399.15 is: 550.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.79 : 917.30 = 399.15 : x
  2. Step 2: Convert to fraction form
    664.79/917.30 = 399.15/x
  3. Step 3: Cross multiply
    664.79x = 917.30 × 399.15
  4. Step 4: Simplify right side
    664.79x = 366,138.30
  5. Step 5: Solve for x
    x = 366,138.30/664.79
  6. Step 6: Final answer
    x = 550.76

Related Problems

Find fourth proportional to 332.39, 458.65 and 199.58
Half scale
Find fourth proportional to 1,329.57, 1,834.59 and 798.30
Double scale
Find fourth proportional to 665.79, 918.67 and 400.15
Similar ratio
Find fourth proportional to 997.18, 1,375.94 and 598.73
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.