Answer:
Step-by-step explanation:
Joint variations occurs when one variable depends on the value of two or more variables. The variable varies directly or indirectly with the other variables combined together. The other variables are held constant. From the given examples, the equation(s) that represent joint variations are
1) z = 3x/y
z varies directly with x and inversely with y.
2) w = abc/4
w varies inversely with a,b and c. 4 is the value of the constant of variation.
To find conjecture about regular polygon, use the formula

Where, n = number of sides of the regular polygone
1) Triangle
n =3
So, Conjecture of the triangle =

= 120
2) Square
n =4
So, Conjecture of the square =

= 90
3) Pentagone
n = 5
So, Conjecture of the pentagon =

= 72
4) Hexagone
n = 6
So, Conjecture of the pentagon =

= 60.
The circumference of a circle is equal to C=2πr
From the question, we have 615.44.
Assume that pi is equal to 3.14
Substitute and solve for r
615.44= 2(3.14)r
r= 615.44/ 6.28
r=98.4704
r=98
Therefore, the radius is about 98 units.
To check:
C=2πr
C=2 x 3.14 x 98
C=6.28 x98
C=615.44
Sum of angles of a linear pair = 180. So angle with measurement 142 and the adjacent angle to it have a sum = 180.
THerefore 142+y=180
Subtracting 142 from both sides
y = 38
Now in the down right sides corner triangle
38+49+w=180
87+w=180
Subtracting 80 from both sides,
w = 93
So the measurement of angle w = 93 .