30. Landscaping Calculate the area (in square feet) of a flower garden shaped like a circular sector withradius 60 ft and central angle 33 degrees.31. In problem 30; if shrubs are planted every 2 ft along the outer border of the garden, how many shrubsare needed?

Respuesta :

[tex]\begin{gathered} 30)\text{Area}_{sc}=1036.72ft^2 \\ 31)Number\text{ of shrubs=}78 \end{gathered}[/tex]

Explanation

the area of a circular sector is given by

[tex]\begin{gathered} \text{Area}_{sc}=\frac{\theta}{360}\pi r^2 \\ \text{where r is the radius and }\theta\text{ is the angle in degr}ees \end{gathered}[/tex]

then

Step 1

Let

[tex]\begin{gathered} \text{radius}=\text{ 60 ft} \\ \text{angle}=33\text{ \degree} \end{gathered}[/tex]

now, replace in the formula

[tex]\begin{gathered} \text{Area}_{sc}=\frac{\theta}{360}\pi r^2 \\ \text{Area}_{sc}=\frac{33}{360}\pi(60ft)^2 \\ \text{Area}_{sc}=1036.72ft^2 \\ \text{rounded} \\ \text{Area}_{sc}=1036.72ft^2 \end{gathered}[/tex]

Step 2

if shrubs are planted every 2 ft along the outer border of the garden, how many shrubs

are needed?

to figure out this, we need to take the perimeter of the circular sector and divide by 2 ft, to get the total number of shrubs in the border

so,

[tex]\text{perimeter}=(2\cdot\text{radius)}+length\text{ of arc}[/tex]

so, we need to find the length of the arc

the length of the arc is given by

[tex]l=\frac{2\pi r}{360}\cdot\theta[/tex]

replace.

[tex]\begin{gathered} l=\frac{2\pi r}{360}\cdot\theta \\ l=\frac{2\pi\cdot60}{360}\cdot33 \\ l=34.55 \end{gathered}[/tex]

finally, replace in the perimeter formula

[tex]\begin{gathered} \text{perimeter}=(2\cdot\text{radius)}+length\text{ of arc} \\ \text{perimeter}=(2\cdot60ft\text{)}+34.55 \\ \text{perimeter}=120\text{ ft+34.55 ft} \\ \text{Perimeter}=154.55\text{ ft} \end{gathered}[/tex]

divde by 2 to know the numbers of shrubs

[tex]\begin{gathered} Numbver\text{ of shrubs=}\frac{\text{ perimeter}}{2})=\frac{154.55\text{ ft}}{2} \\ Numbver\text{ of shrubs=}77.275\text{ ft} \\ Numbver\text{ of shrubs=}78 \end{gathered}[/tex]

Ver imagen VardanJ740489