15. [4] insufficient information. only given SA
16. There are 3 right triangles, 3 Pythagorean theorem equations
x²+b²= 16²
12²+a² = x²
a²+4² = b²
combine equations using substitution to get in terms of only x
substitute b² for (a² +x²) in first equation
x²+a²+4²=16²
substitute a² for (x² - 12²)
x²+x²-12²+4² = 16²
solve for x
2x² - 144 + 16 = 256
2x² = 256 + 144 - 16
2x² = 384
x² = 384/2
x² = 192
x = 13.85
rounded to nearest tenth, x = 13.9
Probably y = 8x. 56 = 8(7), so that works. Without more data, I couldn't say if it could be something else, so that's what I go with.
Answer: In the figure AB is about 8.4 inches and AC is about 13.05 inches.
Step-by-step explanation: We can use cosine to find the hypotenuse. 
Using a calculator x is about 13.05
Using tangent we can find the length opposite of <C

Using a calculator x would be about 8.4
Answer:
Step-by-step explanation:
Conic section (or simply conic) is a curve obtained as the intersection of the surface of a cone with a plane. The three types of conic section are the hyperbola, the parabola, and the ellipse. The circle is a special case of the ellipse, previously called the fourth type. Planes that pass through the vertex of the cone will intersect the cone in a point, a line or a pair of intersecting lines, called degenerate conics.