Answer:
55+x+74+54= 180 degree ( being the sum of all angle of the triangle )
or, 183 +x = 180degree
or, x=(180-183)degree
or, x= -3degree ans
Given:
Circle C and circle R are similar.
The length of arc AB is 
The radius of circle C (AC) = 4 unit
The radius of circle R (QR) =6 unit
To find the length of arc QP.
Formula
The relation between s, r and
is

where,
s be the length of the arc
r be the radius
be the angle.
Now,
For circle C
Taking r = 4
According to the problem,

or,
[ eliminating
from both side]
or, 
or, 
Again,
For circle R
Taking, r = 6 and
we get,
The length of arc QP is

or, 
Hence,
The length of QP is
. Option C.
Answer:
Whether or not a given isotope is radioactive is a characteristic of that particular isotope. Some isotopes are stable indefinitely, while others are radioactive and decay through a characteristic form of emission. As time passes, less and less of the radioactive isotope will be present, and the level of radioactivity decreases. An interesting and useful aspect of radioactive decay is half-life, which is the amount of time it takes for one-half of a radioactive isotope to decay. The half-life of a specific radioactive isotope is constant; it is unaffected by coTnditions and is independent of the initial amount of that isotope.