The obtuse angle was divided into three parts, one 40%, another 20% and the third 78 degrees. Above the obtuse angle.

Let’s denote the obtuse angle value as 100%.

Since the first angle is 40% and the second 20% of the entire angle, their sum is:

40% + 20% = 60%.

So the percentage of the third angle will be:

10% – 60% = 40% (of the whole corner).

Thus, the obtuse angle will be:

78/40% / 10% = 78 / 0.4 = 195 degrees.

The second angle is:

195 * 20% = 195 * 0.2 = 39 degrees.

We check:

78 + 39 + 78 = 195 degrees.

Answer:

The obtuse angle is 195 degrees.