Answer:
16. Angle C is approximately 13.0 degrees.
17. The length of segment BC is approximately 45.0.
18. Angle B is approximately 26.0 degrees.
15. The length of segment DF "e" is approximately 12.9.
Step-by-step explanation:
<h3>16</h3>
By the law of sine, the sine of interior angles of a triangle are proportional to the length of the side opposite to that angle.
For triangle ABC:
- ,
- The opposite side of angle A ,
- The angle C is to be found, and
- The length of the side opposite to angle C .
.
.
.
Note that the inverse sine function here is also known as arcsin.
<h3>17</h3>
By the law of cosine,
,
where
- , , and are the lengths of sides of triangle ABC, and
- is the cosine of angle C.
For triangle ABC:
- ,
- ,
- The length of (segment BC) is to be found, and
- The cosine of angle A is .
Therefore, replace C in the equation with A, and the law of cosine will become:
.
.
<h3>18</h3>
For triangle ABC:
- ,
- ,
- , and
- Angle B is to be found.
Start by finding the cosine of angle B. Apply the law of cosine.
.
.
.
<h3>15</h3>
For triangle DEF:
- The length of segment DF is to be found,
- The length of segment EF is 9,
- The sine of angle E is , and
- The sine of angle D is .
Apply the law of sine:
.
Answer:
42 ft²
Step-by-step explanation:
Rectangle Area: L * W
Answer:
30
Step-by-step explanation:
Note that, when two negative signs are directly next to each other, they mean addition. Note the rule:
A positive sign & A positive sign = Positive number.
A positive sign & A negative sign = Negative number.
A negative sign & A negative sign = Positive number.
In this case:
- (-15) = + 15
Simplify. Combine like terms:
15 + 15 = 30
30 is your answer.
~
If is the first number in the progression, and is the common ratio between consecutive terms, then the first four terms in the progression are
We want to have
In the second equation, we have
and in the first, we have
Substituting this into the second equation, we find
So now we have
Then the four numbers are