The rule to remember for this problem is: i^2 = -1
(4 + i)(1 - 5i)
4 - 20i + i - 5i^2
4 - 19i + 5
9 - 19i
The survey was intended for Bill's middle school during the summer. The
survey was administered to students of other schools on a Saturday.
- The type of error is the <u>selection bias error</u>.
Reasons:
The type of error made is a non sampling error, given that the target of the
study is the number of times in a week students at his middle school
attend the beach during the summer.
The errors are; Selection bias error.
- The given that the students survey are not from his middle school.
- The survey was carried out once on a Saturday, where the target was during the summer.
The selection bias error is a type error that is due to the researcher
chooses what to study, such that the participant have common
characteristics rather than being random.
Learn more about selection bias error here:
brainly.com/question/13727092
Answer:
A: 5:1
B. 2:10
Step-by-step explanation:
Please mark brainliest!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
First of all, we have to observe this triangles separated by the height. These small and big triangles are similar according to the Angle-Angle-Angle principle.
a. We can find all of these length using the cosine of the angle, Pythagoras theorem and the principle of the similarity of triangles.
b. According to the cosine of the angle we can write that, cosθ = 12/a = 5/13 and from here a = 31.2. After finding that using Pythagoras theorem, we can write that 
. According to the similarity of the triangles, we can write that 31.2/d = 28.8/12 and d = 13. Applying Pythagoras theorem we find that c = 5.
c. We already gave the answer for this question in part b
