Answer:
12 square cm correct to 2 significant figures
Step-by-step explanation:
Area of a Rectangle = L X B = 2.1 X 5.6 = 11.76 square cm
To round your result to 2 significant figure, we start counting from the left from the first non-zero digit.
The first two digits are 11 but because the number after is 7 (greater than 4), we round up to 12.
11.76 square cm = 12 square cm correct to 2 significant figures
20% of 200 is 40, so H is the correct answers the proportion can be written as 40:200
Given:
Sides of triangles in the options.
To find:
Which could NOT be the lengths of the sides of a triangle.
Solution:
Condition for triangle:
Sum of two smaller sides of a triangle must be greater than the longest side.
In option A,

Sides 5 in, 5 in, 5 in are the lengths of the sides of a triangle.
In option B,

Sides 10 cm, 15 cm, 20 cm are the lengths of the sides of a triangle.
In option C,

Sides 3 in, 4 in, 5 in are the lengths of the sides of a triangle.
In option D,

Since, the sum of two smaller sides is less than the longest side, therefore the sides 8 ft, 15 ft, 5 ft are not the lengths of the sides of a triangle.
Therefore, the correct option is D.