Mathematics, 27.05.2021 02:20 isabeljackson562

Find the area of a circle with a diameter of 22 millimeters. Round to the nearest tenth.
A 380.1 mm2
B 319.5 mm2
C 189.9 mm2
D 69.1 mm?

Answers: 3

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Answers

Answer from: mrashrafkotkaat

A. 380.1 mm²

General Formulas and Concepts:

Symbols

π (pi) ≈ 3.14

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Geometry

Area of a Circle Formula: A = πr²

r is radius

Radius Formula: $\displaystyle r = \frac{d}{2}$

d is diameter

Step-by-step explanation:

Step 1: Define

Identify variables

d = 22 mm

Step 2: Derive

Rewrite formula

[Area of a Circle Formula] Substitute in r [Radius Formula]: $\displaystyle A = \pi (\frac{d}{2})^2$ Evaluate exponents: $\displaystyle A = \pi (\frac{d^2}{4})$ Multiply: $\displaystyle A = \frac{\pi d^2}{4}$

Step 3: Solve for A

Substitute in variables [Modified Area of a Circle Formula]: $\displaystyle A = \frac{3.14(22 \ mm)^2}{4}$ Evaluate exponents: $\displaystyle A = \frac{3.14(484 \ mm^2)}{4}$ Multiply: $\displaystyle A = \frac{1520.53 \ mm^2}{4}$ Divide: $\displaystyle A = 380.133 \ mm^2$ Round: $\displaystyle A \approx 380.1 \ mm^2$

Answer from: Quest

mr. flanders’ class sold 47 doughnuts and mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations:

$\left\{\begin{array}{l}x+y=85\\1.35x+1.08y=104.49\end{array}\right.\rightarrow \left\{\begin{array}{l}x=85-y\\1.35(85-y)+1.08y=104.49\end{array}\right.$

$114.75-1.35y+1.08y=104.49,\\ \\114.75-104.49=1.35y-1.08y,\\ \\10.26=0.27y,\\ \\y=38,\\ \\x=85-38=47.$

Answer from: Quest

The answer is 16.64 feetyour welcome

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Find the area of a circle with a diameter of 22 millimeters. Round to the nearest tenth.
A 38...

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