I’m guessing the answer would be the last one !
Ten percent of 640 is 64.
640/100=6.4
6.4*10=64.
There are many other ways to find this but that is the way I have always used :)
Hope this helps!
The value of c for which the considered trinomial becomes perfect square trinomial is: 20 or -20
<h3>What are perfect squares trinomials?</h3>
They are those expressions which are found by squaring binomial expressions.
Since the given trinomials are with degree 2, thus, if they are perfect square, the binomial which was used to make them must be linear.
Let the binomial term was ax + b(a linear expression is always writable in this form where a and b are constants and m is a variable), then we will obtain:

Comparing this expression with the expression we're provided with:

we see that:

Thus, the value of c for which the considered trinomial becomes perfect square trinomial is: 20 or -20
Learn more about perfect square trinomials here:
brainly.com/question/88561
Answer:
117 cm²
Step-by-step explanation:
area of rectangle = 13 * 7 = 91cm²
area of upper one right angle triangle= 1/2 * 6.5 * 4 =13 cm²
area of both triangles = 13 cm² * 2 = 26 cm²
Total area = 91cm² + 26 cm²
--> 117 cm²