Home / 830.40-1,239.35-765.28

Finding the Fourth Proportional to 830.40, 1,239.35 and 765.28

Calculator

Solution

The fourth proportional to 830.40, 1,239.35 and 765.28 is: 1,142.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.40 : 1,239.35 = 765.28 : x
  2. Step 2: Convert to fraction form
    830.40/1,239.35 = 765.28/x
  3. Step 3: Cross multiply
    830.40x = 1,239.35 × 765.28
  4. Step 4: Simplify right side
    830.40x = 948,449.77
  5. Step 5: Solve for x
    x = 948,449.77/830.40
  6. Step 6: Final answer
    x = 1,142.16

Related Problems

Find fourth proportional to 415.20, 619.68 and 382.64
Half scale
Find fourth proportional to 1,660.80, 2,478.70 and 1,530.56
Double scale
Find fourth proportional to 831.40, 1,240.84 and 766.28
Similar ratio
Find fourth proportional to 1,245.60, 1,859.03 and 1,147.92
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.