Question

find the figure of the perimeter. Use 3.14 for pi. The figure is not to scale, round to at least one decimal place. NO LINKS!!! ​

Answer 1

Perimeter of semicircle

• πr
• 2π
• 6.28

#Rectangle

• 2(6+4)
• 2(10)
• 20ft-4(2)=12ft

For triangle

Use Pythagorean theorem

• H²=4²+²=16+4=20
• H=4.5

Total Perimeter

• 12+6.5+6.28
• 24.78ft

Answer 2

24.8 ft (1 dp)

Explanation:

Arc length of semicircle =
`\pi r` (where r is the radius)

Given:

• diameter = 4 ft
• ⇒ radius = 4 ÷ 2 = 2ft
• 
  `\pi` = 3.14

⇒ Arc length = 2 × 3.14 = 6.28 ft

Use Pythagoras' Theorem
`a^2+b^2=c^2` to find the hypotenuse of the right triangle with legs 2 ft and 4 ft:

`\implies 2^2+4^2=c^2`

`\implies c^2=20`

`\implies c=√(20)=2√(5)\:\sf ft`

Therefore:

perimeter = 6 + 6.28 + 6 + 2 + 2√5

= 24.75213596...

= 24.8 ft (1 dp)