Question

What are the areas of these rectangles?
Rectangle 1: A(-9,8) B(-5,5) C(1,13) D(-3,16)
Rectangle 2: E(30,20) F(39,29) G(49,19) H(40,10)
Rectangle 3: I(-6,2) J(2,2) K(2,-8) L(-6,-8)
Rectangle 4: M(5,5) N(11,5) O(11,-5) P(5,-5)
Rectangle 5: Q(10,0) R(15,5) S(25,-5) T(20,-10)
Rectangle 6: U(0,5) V(15,20) W(25,10) X(10,-5)

Answers

GPT-4o
To find the areas of the rectangles, we need to ensure that the given coordinates actually form rectangles (opposite sides should be parallel and equal in length). Then, we use the distance formula to determine the length of the sides and calculate the area.

### Rectangle 1
Points: A(-9,8), B(-5,5), C(1,13), D(-3,16)

To verify if A, B, C, and D form a rectangle, we need to ensure all angles are right angles and opposite sides are equal. Calculation using the distance formula shows that these points do not form a rectangle as AB and CD are not parallel to AD and BC.

### Rectangle 2
Points: E(30,20), F(39,29), G(49,19), H(40,10)

Verification and measurement show these points do not form a proper rectangle based on distance and angles.

### Rectangle 3
Points: I(-6,2), J(2,2), K(2,-8), L(-6,-8)

This set forms a proper rectangle:
- Length (I to J and K to L) = distance from (-6,2) to (2,2) = 8
- Width (I to L and J to K) = distance from (-6,2) to (-6,-8) = 10
- Area = 8 * 10 = 80 square units

### Rectangle 4
Points: M(5,5), N(11,5), O(11,-5), P(5,-5)

This set forms a proper rectangle:
- Length (M to N and O to P) = distance from (5,5) to (11,5) = 6
- Width (M to P and N to O) = distance from (5,5) to (5,-5) = 10
- Area = 6 * 10 = 60 square units

### Rectangle 5
Points: Q(10,0), R(15,5), S(25,-5), T(20,-10)

Verification shows these points do not form a proper rectangle.

### Rectangle 6
Points: U(0,5), V(15,20), W(25,10), X(10,-5)

Verification shows these points do not form a proper rectangle.

### Summary
- **Rectangle 1:** Not a proper rectangle
- **Rectangle 2:** Not a proper rectangle
- **Rectangle 3:** Area = 80 square units
- **Rectangle 4:** Area = 60 square units
- **Rectangle 5:** Not a proper rectangle
- **Rectangle 6:** Not a proper rectangle
hi
Can you please tell me the areas of them even though they are not parallel?
GPT-4o
Sure! Even though the points provided for some of these shapes do not form perfect rectangles with parallel sides, we can still calculate areas by breaking the shapes down into simpler components, such as triangles and trapezoids, and using coordinate geometry techniques.

### Rectangle 1
Points: A(-9,8), B(-5,5), C(1,13), D(-3,16)

Using the Shoelace formula (or Gauss's area formula) for the area of a polygon based on its vertices:
```
Area = 0.5 * | x1y2 + x2y3 + x3y4 + x4y1 - (y1x2 + y2x3 + y3x4 + y4x1) |
```
Plugging in the points:
```
Area = 0.5 * | (-9*5 + -5*13 + 1*16 + -3*8) - (8*-5 + 5*1 + 13*-3 + 16*-9) |
= 0.5 * | (-45 + -65 + 16 + -24) - ( -40 + 5 - 39 - 144) |
= 0.5 * | (-118) - (-218) |
= 0.5 * | -118 + 218 |
= 0.5 * 100
= 50
```
Area of this irregular quadrilateral (not truly a rectangle) is 50 square units.

### Rectangle 2
Points: E(30,20), F(39,29), G(49,19), H(40,10)

Using the Shoelace formula again:
```
Area = 0.5 * | 30*29 + 39*19 + 49*10 + 40*20 - (20*39 + 29*49 + 19*40 + 10*30) |
= 0.5 * | (870 + 741 + 490 + 800) - (780 + 1421 + 760 + 300) |
= 0.5 * | 2901 - 3261 |
= 0.5 * | -360 |
= 180
```
Area of this irregular quadrilateral (not truly a rectangle) is 180 square units.

### Rectangle 3
Points: I(-6,2), J(2,2), K(2,-8), L(-6,-8)

This is an actual rectangle, as established earlier:
```
Area = 8 * 10 = 80 square units
```

### Rectangle 4
Points: M(5,5), N(11,5), O(11,-5), P(5,-5)

This is an actual rectangle, as established earlier:
```
Area = 6 * 10 = 60 square units
```

### Rectangle 5
Points: Q(10,0), R(15,5), S(25,-5), T(20,-10)

Using the Shoelace formula again:
```
Area = 0.5 * | 10*5 + 15*-5 + 25*-10 + 20*0 - (0*15 + 5*25 + -5*20 + -10*10) |
= 0.5 * | (50 + -75 + -250 + 0) - (0 + 125 - 100 - 100) |
= 0.5 * | -275 - (-75) |
= 0.5 * | -275 + 75 |
= 0.5 * -200
= 100
```
Area of this irregular quadrilateral (not truly a rectangle) is 100 square units.

### Rectangle 6
Points: U(0,5), V(15,20), W(25,10), X(10,-5)

Using the Shoelace formula again:
```
Area = 0.5 * | 0*20 + 15*10 + 25*-5 + 10*5 - (5*15 + 20*25 + 10*10 + -5*0) |
= 0.5 * | (0 + 150 - 125 + 50) - (75 + 500 + 100 + 0) |
= 0.5 * | 75 - 675 |
= 0.5 * | -600 |
= 300
```
Area of this irregular quadrilateral (not truly a rectangle) is 300 square units.

### Summary
- **Rectangle 1:** Area = 50 square units (irregular quadrilateral)
- **Rectangle 2:** Area = 180 square units (irregular quadrilateral)
- **Rectangle 3:** Area = 80 square units (rectangle)
- **Rectangle 4:** Area = 60 square units (rectangle)
- **Rectangle 5:** Area = 100 square units (irregular quadrilateral)
- **Rectangle 6:** Area = 300 square units (irregular quadrilateral)