Question

Will mark brainliest! Questions are in the picture!

Answer 1

Answer:

52.9 inches .

Step-by-step explanation:

Given that the triangular indentation has an area of 100 in.² and the base and height of this traingle are represented by expressions 3x and x+3 respectively . We need to find out the perimeter to the nearest tenth.

As we know that the area of triangle is ,

$\rm\longrightarrow Area_{\triangle}=\dfrac{1}{2}(base)(height)$

Substituting the respective values,

$\rm\longrightarrow 100\ =\dfrac{1}{2}(x+3)(3x)\\\\\rm\longrightarrow 2(100) = 3x(x+3)\\\\\rm\longrightarrow200 = 3x^2+9x\\\\\rm\longrightarrow 3x^2+9x-200=0$

On using the Quadratic formula , we have;

$\rm\longrightarrow x =\dfrac{-9\pm\sqrt{9^2-4(3)(-200)}}{2(3)} \\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{81+1200}}{6}\\\\\rm\longrightarrow x =\dfrac{-9\pm \sqrt{1281}}{6}$

On simplifying above , we will get ,

$\rm\longrightarrow x = 6.802,-9.802$

Since sides can't be negative, therefore,

$\rm\longrightarrow\underline{\underline{ x =6.802}}$

Therefore ,

• $\rm\longrightarrow Base = 3x =3(6.802)in = 20.406\ in$
• $\rm\longrightarrow Height = x +3=6.802+3=9.802\ in$

Next let's find out the hypotenuse using Pythagoras theorem, as ;

$\rm\longrightarrow h=\sqrt{ b^2+p^2}$

$\rm\longrightarrow h =\sqrt{ (20.406)^2+(9.802)^2}$

$\rm\longrightarrow h =\sqrt{416.40+96.07}$

$\rm\longrightarrow h = 22.63\ in$

Now we may find perimeter as ,

$\rm\longrightarrow P = p + b + h$

$\rm\longrightarrow P = (22.63 + 9.802 + 20.406)in.$

$\\\rm\longrightarrow P = 52.89 \ in.$

$\rm\longrightarrow \underline{\underline{ Perimeter = 52.9\ in .}}$