Home / 979.80-1,351.80-630.72

Finding the Fourth Proportional to 979.80, 1,351.80 and 630.72

Calculator

Solution

The fourth proportional to 979.80, 1,351.80 and 630.72 is: 870.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.80 : 1,351.80 = 630.72 : x
  2. Step 2: Convert to fraction form
    979.80/1,351.80 = 630.72/x
  3. Step 3: Cross multiply
    979.80x = 1,351.80 × 630.72
  4. Step 4: Simplify right side
    979.80x = 852,607.30
  5. Step 5: Solve for x
    x = 852,607.30/979.80
  6. Step 6: Final answer
    x = 870.19

Related Problems

Find fourth proportional to 489.90, 675.90 and 315.36
Half scale
Find fourth proportional to 1,959.60, 2,703.60 and 1,261.44
Double scale
Find fourth proportional to 980.80, 1,353.18 and 631.72
Similar ratio
Find fourth proportional to 1,469.70, 2,027.70 and 946.08
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.