solution

src/figuresClasses.ts

@@ -1,11 +1,92 @@
-export interface Figure {}
+type Shape = 'triangle' | 'circle' | 'rectangle';
+type Color = 'red' | 'green' | 'blue';
 
-export class Triangle implements Figure {}
+export interface Figure {
+  shape: Shape;
+  color: Color;
+  getArea: Function;
+}
+
+export class Triangle implements Figure {
+  public shape: Shape = 'triangle';
+
+  constructor(
+    public color: Color,
+    public a: number,
+    public b: number,
+    public c: number,
+  ) {
+    if (a <= 0) {
+      throw new Error('Side a must be greater than zero');
+    }
+
+    if (b <= 0) {
+      throw new Error('Side b must be greater than zero');
+    }
+
+    if (c <= 0) {
+      throw new Error('Side c must be greater than zero');
+    }
+
+    if (a + b <= c) {
+      throw new Error('Invalid triangle sides: a + b must be greater than c');
+    }
+
+    if (b + c <= a) {
+      throw new Error('Invalid triangle sides: b + c must be greater than a');
+    }
+
+    if (a + c <= b) {
+      throw new Error('Invalid triangle sides: a + c must be greater than b');
+    }
+  }
+
+  getArea = (): number => {
+    const p = 0.5 * (this.a + this.b + this.c);
 
-export class Circle implements Figure {}
+    return (
+      Math.floor(
+        Math.sqrt(p * (p - this.a) * (p - this.b) * (p - this.c)) * 100,
+      ) / 100
+    );
+  };
+}
+
+export class Circle implements Figure {
+  public shape: Shape = 'circle';
+
+  constructor(
+    public color: Color,
+    public radius: number,
+  ) {
+    if (radius <= 0) {
+      throw new Error('Radius must be greater than zero');
+    }
+  }
+
+  getArea = (): number => Math.floor(Math.PI * this.radius ** 2 * 100) / 100;
+}
 
-export class Rectangle implements Figure {}
+export class Rectangle implements Figure {
+  public shape: Shape = 'rectangle';
+
+  constructor(
+    public color: Color,
+    public width: number,
+    public height: number,
+  ) {
+    if (width <= 0) {
+      throw new Error('Width must be greater than zero');
+    }
+
+    if (height <= 0) {
+      throw new Error('Height must be greater than zero');
+    }
+  }
+
+  getArea = (): number => Math.floor(this.width * this.height * 100) / 100;
+}
 
-export function getInfo(figure): string {
-  return typeof figure;
+export function getInfo(figure: Figure): string {
+  return `A ${figure.color} ${figure.shape} - ${figure.getArea()}`;
 }