Step-by-step explanation:
1. ΔABC=ΔCDE: a) according to the condition BC=CD and AC=CE; b) m∠(BCA)=m∠(DCE).
2. if ΔABC=ΔCDE, then m∠(BAC)=m∠(DEC) and m∠(ABC)=m∠(CDE).
3. if m∠(BAC)=m∠(DEC), then AB || DE (or if m∠(ABC)=m∠(CDE), then AB || DE).
Answer: A=70 square units
Step-by-step explanation:
The area of a triangle can be found using the formula 
Let 5=h and 7=b
Plug in the values and solve


However, since four of these triangles make up this rhombus, we can multiply the area of one of these triangles by four to find the area of the whole rhombus.


Using a 1-sample z-interval for the population proportion with confidence level 0.997, the sample probability is 0.69 with margin of error of 0.16, so between 0.69+0.16=0.85 of the population and 0.69-0.16=0.53 of the population prefers coffee. 84% and 54% are the correct answers.
The region bounded by the parabola and the x-axis is symmetric, so any inscribed rectangle whose base lies in the x-axis will have its base extend symmetrically around the origin, i.e. if the base has length

, with

, then its base is the line segment connecting the points

and

.
The height of such a rectangle will then by

.
The area of such a rectangle is then a function of

:

Differentiating with respect to

gives

which has critical points at

We omit the negative root. Checking the sign of the second derivative at the positive critical point (it's negative) confirms that

is the site of a local maximum.
This means the largest area of this rectangle is