Answer:
4: 3
Step-by-step explanation:
In this case, we have that there is a relationship between width and height, which is 16: 9, which means that any screen that has the same ratio would be an identical screen.
How would we do this? it must either be raised to a power or rationalized on both sides of the ratio.
If we raise to a power, it would give very large dimensions for an HDTV, therefore, it is best to remove the square root on both sides, since it has more common values for a TV.

4: 3
Therefore, a 4: 3 screen is a good choice for an HDTV with the same ratio.
Answer: The ΔVZX and ΔWXZ are not congruent by SAS.
Explanation:
It is given that the VX = WZ = 40 cm and ∠ZVX = ∠XWZ = 22°.
Draw a figure as shown below,
According to the SAS rule of congruence, two triangles are congruent if two sides and their inclined angle is equal.
From the given figure it is easily noticed that in ΔVZX and ΔWXZ,
(given)
(given)
(common side)
Since we have two sides and one angle is same. but we can not conclude that the ΔVZX and ΔWXZ are congruent by SAS, because the given angle is not the inclined angle of both equal sides.
Therefore, the ΔVZX and ΔWXZ are not congruent by SAS.
Answer:
Range = 13
Mean = 8.4
Variance= 21.24
Standard deviation= 4.61
Step-by-step explanation:
2, 10, 15, 3, 13, 9, 14, 7, 2, 9
For the range
Let the set of data be arranged inn ascending order
Range= higehest value- lowest value
Range = 15-2
Range= 13
For the mean
Mean = (2+2+3+7+9+9+10+13+14+15)/10
Mean = 84/10
Mean = 8.4
For variance
Variance=((2-8.4)²+(2-8.4)²+(3-8.4)²+(7-8.4)²+(9-8.4)²+(9-8.4)²+(10-8.4)²+(13-8.4)²+(14-8.4)²+(15-8.4)²)/10
Variance= (40.96+40.96+29.16+1.96+0.36+0.36+2.56+21.16+31.36+43.56)/10
Variance= 212.4/10
Variance= 21.24
Standard deviation= √variance
Standard deviation= √21.24
Standard deviation= 4.609
Approximately = 4.61