Answer:
About 3 years Speedy Jet printers be guaranteed.
Step-by-step explanation:
Given : Quality control studies for Speedy Jet Computer Printers show the lifetime of the printer follows a normal distribution with
mean 
and standard deviation 
If the company wishes to replace no more than 10% of the printers.
To find : How long should Speedy Jet printers be guaranteed ?
Solution :
Using Z- table,
Z value corresponding to 10% or 0.10 = -1.28.
Applying z-score formula,
The value of x is given by,
Substitute the values,
So, approx 3 years.
Therefore, About 3 years Speedy Jet printers be guaranteed.
The answer for this question is 9 I
The given conclusion that ABCD is a square is not valid.
Given that, AC⊥BD and AC≅BD.
We need to determine if the given conclusion is valid.
<h3>What are the properties of squares?</h3>
A square is a closed figure with four equal sides and the interior angles of a square are equal to 90°. A square can have a wide range of properties. Some of the important properties of a square are given below.
- A square is a quadrilateral with 4 sides and 4 vertices.
- All four sides of the square are equal to each other.
- The opposite sides of a square are parallel to each other.
- The interior angle of a square at each vertex is 90°.
- The diagonals of a square bisect each other at 90°.
- The length of the diagonals is equal.
Given that, the diagonals of a quadrilateral are perpendicular to each other and the diagonals of a quadrilateral are equal.
Now, from the properties of a square, we understood that the diagonals of a square are perpendicular to each other and the diagonals of a square are equal.
So, the given quadrilateral can be a square. But only with these two properties can not conclude the quadrilateral is a square.
Therefore, the given conclusion that ABCD is a square is not valid.
To learn more about the properties of a square visit:
brainly.com/question/20377250.
#SPJ1
Answers: ∠a = 30° ; ∠b = 60° ; ∠c = 105<span>°.
</span>_____________________________________________
1) The measure of Angle a is 30°. (m∠a = 30°).
Proof: All vertical angles are congruent, and we are shown in the diagram that angle A — AND the angle labeled with the measurement of 30°— are vertical angles.
2) The measure of Angle b is 60°. (m∠b = 60<span>°).
Proof: All three angles of a triangle add up to 90 degrees. In the diagram, we can examine the triangle formed by Angle A, Angle B, and a 90</span>° angle. This is a right triangle, and the angle with 90∠ degrees is indicated as such (with the "square" symbol). So we know that one angle is 90°. We also know that m∠a = 30°. If there are three angles in a triangle, and all three angles must add up to 180°, and we know the measurements of two of the three angles, we can solve for the unknown measurement of the remaining angle, which in this case is: m∠b.
90° + 30° + m∠b = 180<span>° ;
</span>180° - (<span>90° + 30°) = m∠b ;
</span>180° - (120°) = m∠b = 60<span>°
</span>___________________________
Now we need to solve for the measure of Angle c (<span>m∠c).
___________________________________________
All angles on a straight line (or straight "line segment") are called "supplementary angles" and must add up to 180</span>°. As shown, Angle c is on a "straight line". The measurement of the remaining angle represented ("supplementary angle" to Angle c is 75° (shown on diagram). As such, the measure of "Angle C" (m∠c) = m∠c = 180° - 75° = 105°.
