QUESTION IMAGE
Question
making an argument will a rectangle that has the same perimeter as △qrs have the same area as the triangle? image of a coordinate grid with triangle qrs (vertices: q(-2, -2), r(0, 2), s(3, -2))
options:
○ yes
- no
explain your reasoning
To solve this, we first analyze the triangle \( \triangle QRS \). From the coordinates, let's find the base and height. The base (along the x - axis) can be calculated as the distance between \( R(-2,-2) \) and \( S(2,-2) \), so base \( b=\vert2 - (-2)\vert = 4 \). The height (vertical distance from \( Q \) to the base \( RS \)): since \( Q \) has a y - coordinate of \( 0 \) and the base is at \( y=-2 \), height \( h=\vert0-(-2)\vert = 2 \).
Step 1: Calculate the area of the triangle
The formula for the area of a triangle is \( A_{triangle}=\frac{1}{2}\times base\times height \).
Substituting \( b = 4 \) and \( h=2 \), we get \( A_{triangle}=\frac{1}{2}\times4\times2=4 \).
Step 2: Calculate the perimeter of the triangle
First, find the lengths of the sides.
- Length of \( RS \): distance between \( R(-2,-2) \) and \( S(2,-2) \) is \( \sqrt{(2 - (-2))^{2}+(-2 - (-2))^{2}}=\sqrt{4^{2}+0^{2}} = 4 \).
- Length of \( RQ \): distance between \( R(-2,-2) \) and \( Q(0,0) \) is \( \sqrt{(0 - (-2))^{2}+(0 - (-2))^{2}}=\sqrt{2^{2}+2^{2}}=\sqrt{4 + 4}=\sqrt{8}=2\sqrt{2}\approx2.83 \).
- Length of \( SQ \): distance between \( S(2,-2) \) and \( Q(0,0) \) is \( \sqrt{(0 - 2)^{2}+(0 - (-2))^{2}}=\sqrt{(-2)^{2}+2^{2}}=\sqrt{4 + 4}=\sqrt{8}=2\sqrt{2}\approx2.83 \).
Perimeter of the triangle \( P_{triangle}=4 + 2\sqrt{2}+2\sqrt{2}=4 + 4\sqrt{2}\approx4+5.66 = 9.66 \).
Step 3: Analyze the rectangle with the same perimeter
Let the length and width of the rectangle be \( l \) and \( w \). The perimeter of a rectangle is \( P = 2(l + w) \). We know \( P=4 + 4\sqrt{2}\), so \( 2(l + w)=4 + 4\sqrt{2}\), which simplifies to \( l + w=2 + 2\sqrt{2}\approx2 + 2.83=4.83 \).
The area of a rectangle is \( A_{rectangle}=l\times w \). By the AM - GM inequality, for positive numbers \( l \) and \( w \), \( \frac{l + w}{2}\geq\sqrt{lw} \), or \( lw\leq(\frac{l + w}{2})^{2} \). Substituting \( l + w = 2 + 2\sqrt{2} \), we have \( (\frac{2 + 2\sqrt{2}}{2})^{2}=(1+\sqrt{2})^{2}=1 + 2\sqrt{2}+2=3 + 2\sqrt{2}\approx3 + 2.83 = 5.83 \). Wait, but we can also try to find integer or simple values. Wait, maybe a better approach: Let's assume the rectangle has perimeter equal to the triangle's perimeter. Let's take the triangle's perimeter \( P = 4+4\sqrt{2}\approx9.66 \). Let's suppose the rectangle has length \( l \) and width \( w \), \( 2(l + w)=9.66\Rightarrow l + w = 4.83 \).
Suppose we try to make the rectangle's area equal to the triangle's area (\( A = 4 \)). So we need \( l\times w=4 \) and \( l + w=4.83 \). The quadratic equation would be \( x^{2}-4.83x + 4 = 0 \). The discriminant \( D=(4.83)^{2}-16=23.3289 - 16 = 7.3289 \), and the roots are \( x=\frac{4.83\pm\sqrt{7.3289}}{2}=\frac{4.83\pm2.71}{2} \). The roots are \( \frac{4.83 + 2.71}{2}=\frac{7.54}{2}=3.77 \) and \( \frac{4.83-2.71}{2}=\frac{2.12}{2}=1.06 \). But let's think about the triangle and rectangle with the same perimeter.
Wait, another way: The triangle has area 4. Let's consider a rectangle with perimeter equal to the triangle's perimeter. Let's take a simple case. Suppose the triangle has perimeter \( P = 4 + 2\sqrt{2}+2\sqrt{2}=4 + 4\sqrt{2}\approx9.66 \). Let's consider a rectangle with length \( l = 3 \) and width \( w \). Then \( 2(3 + w)=9.66\Rightarrow3 + w = 4.83\Rightarrow w = 1.83 \). Area of rectangle \( A = 3\times1.83 = 5.49
eq4 \). If we take \( l = 4 \) and \( w \), \( 2(4 + w)=9.66\Rightarrow4 + w = 4.83\Rightarrow w = 0.83 \), area \( A=4\times0.83 = 3.32
eq4 \).
In general, for a given perimeter, the rectangle with the maximum area is a square (when \( l = w \)…
Snap & solve any problem in the app
Get step-by-step solutions on Sovi AI
Photo-based solutions with guided steps
Explore more problems and detailed explanations
No. The area of \( \triangle QRS \) is calculated as \( \frac{1}{2}\times4\times2 = 4 \). For a rectangle with the same perimeter (\( 4 + 4\sqrt{2}\approx9.66 \)), the maximum area (when it's a square) is \( (1+\sqrt{2})^{2}=3 + 2\sqrt{2}\approx5.83
eq4 \), and other rectangles with this perimeter will have areas different from 4, so the rectangle and the triangle cannot have the same area.