Step-by-step explanation:
a)
a whole circle represents always 360 degrees.
we see the angle J is 72 degrees. the angle K is 90 degrees.
that leaves us for M and L together :
360 - 72 - 90 = 198 degrees.
we now know that twice as many people voted for L as for M. that means the angle L is twice as big as the angle M
on other words : L = 2M
and when we now say
198 = L + M
this means
198 = 2M + M = 3M
M = 66 degrees
and L is then 2M = 2×66 = 132 degrees
b)
again, the whole circle is 360 degrees.
J covers 72 of these 360 degrees.
that is 72/360 of all voting people.
72/360 = 1/5
the total of all voting people was 15840.
so, 1/5 of 15840 is
15840/5 = 3168
that means 3168 people voted for J.