Answer:

Step-by-step explanation:
we know that
An exterior angle of a triangle is equal to the sum of the opposite interior angles.
see the attached figure to better understand the problem
so
∠DEF=∠ECD+∠CDE
substitute the given values

solve for x
Combine like terms

Group terms



Find the measure of angle CDE

substitute the value of x

Ratio of the heights of two similar cones is 7/9
what is the ratio of their radii? ratio of their volumes??
TIA
If they are similar, the ratio of the radaii is the same.
Now consider that the volume of a cone is 1/3 PI r^2 * h
So the volume ratio will have a (7/9)^2 * 7/9 ratio
Divide the circumference by 2 to get the radius which in your case would be 31.4
The sum of the prime numbers 2, 5, and 61 is 68.