Question: What value of c will complete the square below (
) and make the expression a perfect square trinomial?
Answer: c = 225
Step-by-step explanation:
Perfect square trinomials come in the form a² + 2ab + b², which is equal to (a + b)². In the presented trinomial, we can immediately identify that <u>a = x, and b² = c</u>, but we need to find the numerical value of 
.
To do this, note that the middle term, or <u>2ab, corresponds with (is equal to) 30x</u>. We know that a = x, and thus, <u>2ab = 2bx</u>. Now, 2bx and 30x are corresponding terms; thus, <u>2bx = 30x</u>.
Dividing by 
on both sides gives us <u>b = 15</u>. Therefore, c = b² = 15² = 225. (As a squared binomial, this would be (x + 15)² as a = x and b = 15.)
Although there is no picture, I will assume this is a triangle we are talking about since the terms base and height are being used. If that is the case, the height is roughly 38.72in.
To find this, we will use the area of a triangle formula.
1/2bh = a ---> plug in known values.
1/2(12.6)(h) = 244 ---> multiply to simplify
6.3(h) = 244 ----> divide both sides by 6.3
h = 38.73
3/5 is greater because the decimal is .6 while 21/40 is .525
Answer:
16.2 m
Step-by-step explanation:
First, we can draw a picture. The cable goes from the top of the pole to the ground (with the pole on the right in my drawing), and the point on the ground is 10 m away from the base of the pole. This forms a right triangle, with the right angle being between the 10 m distance and the pole itself. We can then apply the Pythagorean Theorem, so
a²+b²=c², with c being the side opposite the right angle (the cable), getting us
10²+(length of pole)² = 19²
19²-10²=(length of pole)²
= 261
square root both sides to isolate the length of the pole
length of pole ≈ 16.2 m
