Home / 780-1,170-347.28

Finding the Fourth Proportional to 780, 1,170 and 347.28

Calculator

Solution

The fourth proportional to 780, 1,170 and 347.28 is: 520.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    780 : 1,170 = 347.28 : x
  2. Step 2: Convert to fraction form
    780/1,170 = 347.28/x
  3. Step 3: Cross multiply
    780x = 1,170 × 347.28
  4. Step 4: Simplify right side
    780x = 406,317.60
  5. Step 5: Solve for x
    x = 406,317.60/780
  6. Step 6: Final answer
    x = 520.92

Related Problems

Find fourth proportional to 390, 585 and 173.64
Half scale
Find fourth proportional to 1,560, 2,340 and 694.56
Double scale
Find fourth proportional to 781, 1,171.50 and 348.28
Similar ratio
Find fourth proportional to 1,170, 1,755 and 520.92
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.