Validation (User Inputs Wrong Data Type?)

[demacade]

I've got a pretty simple program that calculates the area of a triangle. It works fine and returns my error message if the user inputs 0 or a negative number (triBase and triHeight are defined as float earlier in the code), but how do I handle it if the user inputs "four" or "4 feet"?

 {
		cout << "What is the base of the triangle? "; //Collect required information.
		cin >> triBase;

		cout << "What is the height of the triangle? ";
		cin >> triHeight;
			
		if (triBase*triHeight>0) //Checks for invalid data.
		{
			cout << "The area of your rectangle is " << triBase*triHeight << ".\n"; // Calculate and display the area.
		}

	//Returns error message and kills program if one or more inputs is invalid.
	else
		cout << "One or more inputs are invalid.  Please run the program again.\n";
		}