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24 votes
24 votes
Help me w this pls thanks

Help me w this pls thanks-example-1
User Xavier Dury
by
2.6k points

2 Answers

9 votes
9 votes

Answer: 7.14 mm and 3.14 mm²

Explanation:

The perimeter of a figure is the total length on the outside of the figure. A regular circle has a perimeter of
2\pi r, where r is the radius and
\pi is an irrational constant, approximately 3.14.

Due to the right angle, we know that this is a quarter circle, as it is a quarter of 360°, or a full circle. Hence, the curved portion of the quarter circle is
(1)/(4)* 2\pi r or
(1)/(2) \pi r. The radius is 2 mm, so this value is


(1)/(2) \pi*2=\pi

However, this isn't the total perimeter, as there are straight edges in the figure too. Both edges are radii of the whole circle, so both would be 2mm. Their total is


2+2=4

By adding
\pi to 4 we get
\pi +4 or 7.14 mm.

The area is the total space enclosed by a figure. The total area of a whole circle is
\pi r^2, where r is still the radius. Since this is a quarter circle, it would take up a quarter of the area, or
(1)/(4) \pi r^2. We can plug in 2 for r and solve to get the area.


(1)/(4)\pi*2^2\\(1)/(4)\pi*4\\\pi

Hence, the area is
\pi, or around 3.14 mm².

User Niegus
by
2.5k points
27 votes
27 votes

Answer:

Perimeter: 4+
\pi \\ mm

Area:
\pi mm^2

Explanation:

Perimeter:

90/360 * 4
\pi \\ +2 + 2 = 4+
\pi \\

Area:

90/360 * 4
\pi =
\pi

User Andrew Butenko
by
3.1k points