The answer is D) -3 Hope this help
Answer:
<h2>7. 62.8 sq.in.</h2><h2>8. 21.2 sq.in.</h2>
Step-by-step explanation:
The formula of an area of a triangle:
a, b - adjacent sides
θ - included angle
=============================================
7.
a = 9in, b = 14in, θ = 85°
sin85° ≈ 0.9962
Substitute:
8.
a = 12 in, b = 5 in, θ = 135°
sin135° = sin(180° - 45°) = sin45° ≈ 0.7071 <em>used sin(180° - x) = sin(x)</em>
Substitute:
Given:
There exist a proportional relationship between x and y.
To find:
The equation which represents a proportional relationship between x and y.
Solution:
If there exist a proportional relationship between x and y, then
where, k is constant of proportionality.
We know that, proportional relationship passes through the origin because (0,0) satisfy .
For x=0, check which equation has y=0.
In option A, .
In option B, .
In option C, .
In option D,
Only in option C, we have a equation of the form with 4 as constant of proportionality and it passes through (0,0).
<h2><u>Therefore, the correct option is C.</u></h2>
The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .
<u>Step-by-step explanation:</u>
Here we have , Twenty-eight athletes participate in a 100-meter race. The time of each athlete is measured during the qualification round. The average time is 11 seconds. The 8 athletes with the fastest time qualified for the final. The average time of these 8 athletes is 10.5 seconds. Let's have equations for this:
where are athletes
⇒
⇒
⇒
⇒ , where m is average time of the 20 athletes who did not qualify for the final.
⇒
⇒
⇒
∴ The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .