Answer: 
Step-by-step explanation:
The formula for the lateral area of a cone
is:

Where:
is the radius of the circular base of the cone
As we know its diameter
, its radius is 
is the height of the cone

This is the lateral area of the volcano with the shape of a cone
I would assume only one triangle can have these dimensions since the side lengths are so specific
I want to say 81°
Here's how I found that:
The angle 105° is on a straight line showing the outer obtuse angle. A straight line is 180°.
180-105=75.
Therefore that inner angle of the 105° is 75°.
We are also given the top angle of 24°.
All 3 angles of a triangle should add up to 180. So, we get the 75+24=99
180-99=81
Last angle should be 81°
For #1, the biggest piece in the pie chart is hit by car.
For #2, think of a way to keep them alive. Maybe reduced speed limit or something...