The perimeter of the pentagon is 34 inches. Find the length of the side that is unknown. Explain your thinking.
1 answer:
You might be interested in
Answer:
Step-by-step explanation:
Please refer to the image attached with this answer. Assuming our triangle to be ΔABC and Line AD meeting BC at D.
As we are given that side b = side c
The angle subtended by them ∠B and ∠C must be equal . Let us assume them to be x each . hence
x + x + 52° +31° = 180°
2x + 73° = 180°
2x = 180°- 73°
2x = 107 °
x = 53.5°
Hence in ΔACD
x+ 31°+∠2= 180°
53.5°+31°+ ∠2 = 180°
∠2=180°-84.5°
∠2=95.5°
Also
∠1 + ∠2 = 180°
∠1 + 95.5° = 180°
∠1 = 180°-95.5°
∠1 =84.5°
Now applying Sine rule in ΔABD
Hence we have c as 15.14
as we are given that side c = side b , b=15.14
The properties of any triangle says that the sum of two sides of any triangle is always greater than the third side. Hence
a<b+c
12+2x-6<15.14+15.14
6+2x<30.28
2x<30.28-6
2x<24.28
x<12.14
also side a must be greater than 0
12+2x-6>0
6+2x>0
2x>-6
x>-3
Hence the range of x will be
-3 <x < 12.14
We know that
the area of a rectangle=length*width
let
length=x-3
width=x+8
area=42 ft²
so
42=(x-3)*(x+8)----------> x²+8x-3x-24=42--------> x²+5x-66=0
using a graph tool-------> to resolve the second order equation
see the attached figure
the solution is
x=6
hence
length=x-3------> 6-3-----> 3 ft
width=x+8 ------> 6+8----> 14 ft
the answer is
<span>the dimensions of the rectangle are 3 ft x 14 ft</span>
the area of a rectangle=length*width
let
length=x-3
width=x+8
area=42 ft²
so
42=(x-3)*(x+8)----------> x²+8x-3x-24=42--------> x²+5x-66=0
using a graph tool-------> to resolve the second order equation
see the attached figure
the solution is
x=6
hence
length=x-3------> 6-3-----> 3 ft
width=x+8 ------> 6+8----> 14 ft
the answer is
<span>the dimensions of the rectangle are 3 ft x 14 ft</span>