11. (a) Consider a study designed to investigate the following claim. A toothpaste with an active ingredient is effective in reducing
plaque buildup on teeth.
The following design is proposed for the study.
Obtain 170 volunteers from the population of people with plaque buildup on
their teeth. Randomly assign 90 of the volunteers to use the toothpaste with
an active ingredient each day. Assign the remaining 80 volunteers to use a
placebo each day. Observe the number of people who experienced a reduction
of plaque buildup in each group after six months.
Is this an observational study or an experiment? Explain.

solution:

we have to construct

∠m nt ≅ ∠p qr

the steps to draw this construction are

step 1: use a compass to draw an arc from point q which intersects the side pq at point a and the side qr at point b.

step 2: draw a segment nt and use the same width of the compass to draw an arc from point n which intersects the segment nt at a point x.

step 3:

step 4: join points n and y using a straightedge.

step 3:

option (d).maintaining the same width of the compass as ab, draw an arc from point x such that it intersects the arc drawn from n in a point y.

to draw   congruent angles , 1. width of compasses while drawing two angles should be same i.e from point at which angle has to be drawn, 2.the distance between the two points where the compass intersects the two sides should be same while drawing any two congruent angles.

1/3 + 1/3 ≠ 2/6 because 1/3 alone = 2/6  

step by step explanation:

1/3 + 1/3 = 2/3       2/3=4/6

the answer is a.

step-by-step explanation:

in three games of golf, alex shot two under par four times.

is there more to this question?