Home / 413.19-619.79-139.21

Finding the Fourth Proportional to 413.19, 619.79 and 139.21

Calculator

Solution

The fourth proportional to 413.19, 619.79 and 139.21 is: 208.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    413.19 : 619.79 = 139.21 : x
  2. Step 2: Convert to fraction form
    413.19/619.79 = 139.21/x
  3. Step 3: Cross multiply
    413.19x = 619.79 × 139.21
  4. Step 4: Simplify right side
    413.19x = 86,278.72
  5. Step 5: Solve for x
    x = 86,278.72/413.19
  6. Step 6: Final answer
    x = 208.81

Related Problems

Find fourth proportional to 206.60, 309.89 and 69.60
Half scale
Find fourth proportional to 826.38, 1,239.57 and 278.42
Double scale
Find fourth proportional to 414.19, 621.29 and 140.21
Similar ratio
Find fourth proportional to 619.79, 929.68 and 208.81
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.