NOT NECESSARILY would a triangle be equilateral if one of its angles is 60 degrees. To be an equilateral triangle (a triangle in which all 3 sides have the same length), all 3 angles of the triangle would have to be 60°-angles; however, the triangle could be a 30°-60°-90° right triangle in which the side opposite the 30 degree angle is one-half as long as the hypotenuse, and the length of the side opposite the 60 degree angle is √3/2 as long as the hypotenuse. Another of possibly many examples would be a triangle with angles of 60°, 40°, and 80° which has opposite sides of lengths 2, 1.4845 (rounded to 4 decimal places), and 2.2743 (rounded to 4 decimal places), respectively, the last two of which were determined by using the Law of Sines: "In any triangle ABC, having sides of length a, b, and c, the following relationships are true: a/sin A = b/sin B = c/sin C."¹
You're pretty close. It's all in the details.
A. Correct.
B. Correct.
C. Sign error in the boxed answer. -(-0.5) = 0.5
The graph shows c ≈ 1.855. If a is more than that and decreasing, area is increasing. The sign of dA/dt will be positive. (Compare to D)
D. Units are not shown. Numerical value is correct.
One bag of popcorn would cost $6.50
To solve this, we can set up equations:
28p+40c=$282
17p+20c=$160.50
To solve this system, we would need to make either the candy bars the same or the bags of popcorn the same. Since we are solving for bags of popcorn, we will make the candy bars the same:
20(28p+40c=$282)
40(17p+20c=$160.50)
Which would give you:
560p+800c=$5,640
680p+800c=$6,420
Subtract them:
(680p+800c=$6,420)
-(560p+800c=$5,640)
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120p=$780
Now divide by 120 to get the price of one bag of popcorn:
120p=$780
_________
120
p=$6.50
