Answer:
Part 67) 
and 
Part 68) 
or 
Step-by-step explanation:
Part 67) we know that
The solution of the number line is the interval -------> (-2,3)
All real numbers greater than -2 and less than 3
so
The compound inequality could be
and
"And” indicates that, both statements must be true at the same time
Part 68) we know that
The solution of the number line is the interval (-∞,-1] ∪ [1,∞)
All real numbers less than or equal to -1 or all real numbers greater than or equal to 1
The compound inequality could be
or
"Or” indicates that, as long as either statement is true, the entire compound sentence is true
We'll use standard labeling of right triangle ABC, C=90 degrees, legs a, b, hypotenuse c.
11.
Right triangle, cliff peak A, boat B, angle opposite cliff is B=28.9 deg. adjacent leg a=65.7 m, cliff height is leg b.
tan B = b/a
b = a tan B = 65.7 tan 28.9° = 36.3 m
12.
Similar story, boat at B, opposite b=3.5 m, rope c=12 m
sin B = b/c
B = arcsin b/c = arcsin (3.5/12) = 17.0°
13.
c=124 m, A=58°
sin A = a/c
a = c sin A = 124 sin 58 = 105.2 m
14.
That's a hypotenuse c=4-1.2 = 2.8 m to a height b=1.8m so
cos A = b/c
A = arccos b/c = arccos (1.8/2.8) = 50.0°
15.
Not a right triangle, an isosceles triangle. Half of it is a right triangle with hypotenuse one arm, c=9.8 cm and angle opposite half the base of B=62/2=31°. We're after d=2b:
sin B = b/c
b = c sin B
d = 2b = 2 c sin B = 2(9.8) sin 31 = 10.1 cm
Almost equilateral
I have memorized facts about fractions like these, so can tell you ...
_____
A fraction with 9 as a denominator is a repeating 1-digit decimal with the decimal digit being the numerator of the fraction.
A fraction with 11 as a denominator is a repeating 2-digit decimal with the two digits being 9 times the numerator of the fraction.
1/8 = 0.125, so any multiple of 1/8 is that multiple of 0.125.
Your answer is going to be fifteen plus r
Well there has to be a right angle in there somewhere as the pole must be perpendicular to the ground.
Using the sine rule:
sinA/a = sinB/b where a = 10, A = 90, b = 5√3, B = B
Re-arrange for B, B = arcsin (b(sinA)/a)
B = arcsin(5√3(sin90)/10)
B = 60 degrees.
Answer is C
