Home / 780.72-1,170.26-318.30

Finding the Fourth Proportional to 780.72, 1,170.26 and 318.30

Calculator

Solution

The fourth proportional to 780.72, 1,170.26 and 318.30 is: 477.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.72 : 1,170.26 = 318.30 : x
  2. Step 2: Convert to fraction form
    780.72/1,170.26 = 318.30/x
  3. Step 3: Cross multiply
    780.72x = 1,170.26 × 318.30
  4. Step 4: Simplify right side
    780.72x = 372,496.29
  5. Step 5: Solve for x
    x = 372,496.29/780.72
  6. Step 6: Final answer
    x = 477.12

Related Problems

Find fourth proportional to 390.36, 585.13 and 159.15
Half scale
Find fourth proportional to 1,561.43, 2,340.52 and 636.61
Double scale
Find fourth proportional to 781.72, 1,171.76 and 319.30
Similar ratio
Find fourth proportional to 1,171.07, 1,755.39 and 477.45
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.