Math  /  Geometry

QuestionWhat is the area, in square units, of triangle BCD? Triangle BCD, with vertices B(-6,-9), C(-2,-4), and D(-8,-3), is drawn inside a rectangle, as shown below.

Studdy Solution

STEP 1

What is this asking? We need to find the area of a triangle inside a square on a coordinate grid. Watch out! Don't forget to use the coordinate values, not just count squares!

STEP 2

1. Identify the coordinates
2. Calculate the square's area
3. Find the triangle's area
4. Subtract to get the shaded area

STEP 3

Alright, let's get our detective hats on and find those sneaky coordinates!
We've got a square with a triangle inside, and we need to figure out where all the points are hiding.

STEP 4

Let's start with the square.
It's sitting pretty from (9,1)(-9, -1) to (1,7)(-1, 7).
Can you see it?
That's our playground for this problem!

STEP 5

Now, let's name our triangle's vertices.
We've got: - Point B at (9,1)(-9, -1) - Point C at (1,1)(-1, -1) - Point D at (1,7)(-1, 7)
See how they form a right triangle?
That's going to be super helpful later!

STEP 6

Time to size up our square!
We need to find its area, but first, let's figure out its side length.

STEP 7

The square goes from 9-9 to 1-1 on the x-axis.
That's a difference of: 1(9)=1+9=8=8|-1 - (-9)| = |-1 + 9| = |8| = 8 So our square is 8 units wide and 8 units tall.
It's a perfect square!

STEP 8

Now, let's calculate the area.
For a square, we multiply the side length by itself: Area of square=88=64 square units\text{Area of square} = 8 \cdot 8 = 64 \text{ square units}

STEP 9

Now for the star of our show - the triangle!
We're going to use the formula for the area of a triangle: 12baseheight\frac{1}{2} \cdot \text{base} \cdot \text{height}.

STEP 10

Let's find the base and height: - The base is the same as the square's width: 8 units - The height is the same as the square's height: 8 units

STEP 11

Now let's plug these into our formula: Area of triangle=1288=32 square units\text{Area of triangle} = \frac{1}{2} \cdot 8 \cdot 8 = 32 \text{ square units}

STEP 12

We're in the home stretch!
The shaded area is what's left when we take the triangle out of the square.

STEP 13

Let's do the math: Shaded area=Area of squareArea of triangle\text{Shaded area} = \text{Area of square} - \text{Area of triangle} Shaded area=6432=32 square units\text{Shaded area} = 64 - 32 = 32 \text{ square units}

STEP 14

The area of the shaded region (triangle BCD) is **32 square units**.

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