If the measure of the given central angle is
rad, then the length of the subtended arc is
satisfying

It's not clear from the question what the value of
is...
Whenever a number is followed by percent, you can turn it into a fraction by simply moving the decimal places two places to the left:
90.0 % becomes .90
As a fraction, this is 90 over 100. To reduce it to its simplest form, divide by 10:
9/10
Total possible outcomes: (2)³=8 (heads or tails possibility on each toss)
Draw out a Tree diagram to illustrate the given example, labelling the probability on each branch.
Adding all the possible situations with P(t)≥2, we get 0.352 as the probability.
Hope I helped :)
perimeter = 2L+2w
from the problem L = 1/5w-2
so perimeter = 2(1/5w-2) +2w
= 2/5w-4 +2w
=12/5w-4
without seeing your choices it should be similar to this