55 times 30 is 1650 and 30 times 5 is 150
The answer is 1650 over 150
Since the perimeter must not exceed 291.
Let the third side be x.
x + 87 + 64 < 291
x + 151 < 291.
x < 291 -151.
x < 140. (First)
But for a triangle there is what is called the Triangle Inequality Theorem. That given the two sides of a tringle, the third side of the triangle must greater than the positive difference between the two sides and less than the sum of the two sides.
So for this case. 87 and 64.
x > ( 87 - 64). x > 23.
x < (87 + 64) x < 151. Combine both inequalities.
23 < x < 151 (second).
Combining First and second. Both must be satisfied.
So we have a more accurate answer as:
23 < x < 140. x is greater than 23 and x is less than 140.
x could be 24, 25, 26, 27, ......, 139. cm.
I hope this helps.
P(7,6), Q(1,6), R(4,2)
We have PQ parallel to the x axis. We'll call that the base,
b = 7 - 1 = 6
The altitude is then the y difference h = 6 - 2 = 4
The area is 
Answer: 12 square units
In general we can use the shoelace formula for the area of any polygon given coordinates. We write the points like this:
(7,6), (1,6), (4,2)
(1,6), (4,2), (7,6)
The area is then half the absolute value of the sum of the cross products:
