Answer:
See below
Step-by-step explanation:
π, pronounced as <em>pi</em> is the ratio between 2πr which is circumference to 2r which is diameter.
In word, π is circumference/diameter which has exact value of 3.14159... and it is also an irrational number too.
π is often used to be defined as 3, 3.14 or 22/7 [Keep in mind, these numbers are only approximation.] in some fields. In trigonometry, π is mostly used to refer as <u>π radians</u> or <u>π rad</u> which is equivalent to 180°.
Why do we need it? Because it’s useful in a field that requires rotation. If you notice, figure with circular base will always have π with it, the volume is an example.
In calculus, you need π to do solid of revolution method which is:
![\displaystyle \large{V =\pi \int\limits^a_b {[f(x)]^2} \ dx }\\\\\displaystyle \large{V = \pi \int\limits^a_b {[g(y)]^2} \ dy}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Clarge%7BV%20%3D%5Cpi%20%5Cint%5Climits%5Ea_b%20%7B%5Bf%28x%29%5D%5E2%7D%20%5C%20dx%20%7D%5C%5C%5C%5C%5Cdisplaystyle%20%5Clarge%7BV%20%3D%20%5Cpi%20%5Cint%5Climits%5Ea_b%20%7B%5Bg%28y%29%5D%5E2%7D%20%5C%20dy%7D)
In trigonometry, you need it for measurement/angle.
So anything that’s related to revolution, rotation or related to circle must require π at least.
In general life, you do not use it but this is mostly applied in engineering field and anything related to science that involves with circle or revolve.
Let me know if you have any questions!
Mary McDonald sold 11 small mugs and 10 large mugs.
Step-by-step explanation:
Given,
Total cost of sold cups = $85
Cost of one small cup = $2.50
Cost of one large cup = $5.75
Cups at the start of day = 215
Cups at the end of day = 194
Cups sold = Cups at the start of day - Cups at end of day
Cups sold = 215 - 194 = 21
Let,
x represents the number of small cups.
y represents the number of large cups.
According to given statement;
x+y=21 Eqn 1
2.50x+5.75y=85 Eqn 2
Multiplying Eqn 1 by 2.50

Subtracting Eqn 3 from Eqn 2

Dividing both sides by 3.25

Putting in Eqn 1

Mary McDonald sold 11 small mugs and 10 large mugs.
Keywords: linear equation, subtraction
Learn more about linear equations at:
#LearnwithBrainly
(9x - 1)² = <em>81x² - 18x + 1</em>
Answer:
A, D and C.
Step-by-step explanation: