Law of cosines
:
The law of cosines establishes:
general guidelines:
The law of cosines is used to find the missing parts of an oblique triangle (not rectangle) when either the two-sided measurements and the included angle measure are known (SAS) or the lengths of the three sides (SSS) are known.
Law of the sines:
In ΔABC is an oblique triangle with sides a, b, and c, then:
The law of the sines is the relation between the sides and angles of triangles not rectangles (obliques). It simply states that the ratio of the length of one side of a triangle to the sine of the angle opposite to that side is equal for all sides and angles in a given triangle.
General guidelines:
To use the law of the sines you need to know either two angles and one side of the triangle (AAS or ASA) or two sides and an opposite angle of one of them (SSA).
The ambiguous case
:
If two sides and an angle opposite one of them is given, three possibilities may occur.
(1) The triangle does not exist.
(2) Two different triangles exist.
(3) Exactly a triangle exists.
If we are given two sides and an included angle of a triangle or if we are given 3 sides of a triangle, we can not use the law of the sines because we can not establish any proportion where sufficient information is known. In these two cases we must use the law of cosines
Z=95° as opposite angles are equal
The angle next to 120° is 60° as angles on a straight line sum to 180°
This means that y=25° because angles in a triangle sum to 180°
Therefore x=155° as angles on a straight line sum to 180°
Answer:
I just learned this topic and have the same question, so I'm not sure if this right. However, I see a fellow student struggling and have to at least put in what I know. My equation was f(n) = 64(1/2)^n-1, then the question was write an expression to represent f(20).
Step-by-step explanation:
So, my answer was f(20) = 64(1/2)^19
f(20) is the number you plug into n. And because the exponent is n-1, I knew to subtract 1 from 20 to get 19.
Then I just wrote the equation out like the original expect with the numbers pluged in: f(20) = 64(1/2)^19
I hope this helps!
Answer: The cost per game is $5.5
Step-by-step explanation:
Zhang Lei spent $20.00 during his last outing at the bowling alley. There is a one time shoe rental fee of $3.50. He spent the rest of the money on bowling a number of games.
This means that amount paid for x number of games = 20 - 3.5 = $16.5
If it took Zhang Lei 45 minutes to bowl each game and he spent 2 hours and 15 minutes bowling, total time spent in minutes is 120+ 15 = 135 minutes. Therefore, the number of games is played is 135/45 = 3
If the total number of games played cost 16.5, therefore, the cost per game will be 16.5/3 = $5.5
These are the steps, with their explanations and conclusions:
1) Draw two triangles: ΔRSP and ΔQSP.
2) Since PS is perpendicular to the segment RQ, ∠ RSP and ∠ QSP are equal to 90° (congruent).
3) Since S is the midpoint of the segment RQ, the two segments RS and SQ are congruent.
4) The segment SP is common to both ΔRSP and Δ QSP.
5) You have shown that the two triangles have two pair of equal sides and their angles included also equal, which is the postulate SAS: triangles are congruent if any pair of corresponding sides and their included angles are equal in both triangles.
Then, now you conclude that, since the two triangles are congruent, every pair of corresponding sides are congruent, and so the segments RP and PQ are congruent, which means that the distance from P to R is the same distance from P to Q, i.e. P is equidistant from points R and Q
