Answer:
30:
The perimeter must be less than 28 feet.
The triangle has 3 sides
We already know that two sides of the shape are both 7 feet.
We could simply call the missing length of the one side 7.
You know your answer is correct because 7 + 7 + 7 = 21
21 is less than 28
31:
The height is 8 inches. The base is greater than the height.
Since we already have the equation x + 3 for the base, ask yourself 'what plus 3 is greater than 8?' The answer is 6.
The base could be 6+3, or 9 inches. The height can be 8 inches.