Answer:
19 m
Step-by-step explanation:
Perimeter = 2(length + width) ; P = 2(l+w) - - (1)
Area = Length * width ; A = l*w - - - (2)
76 = 2(l+w)
76/2 = l+w
l+w = 38
l = 38 - w
Put l = 38 - w in (1)
A = (38-w)*w
A = 38w - w²
At maximum point:
dA/dw = 0
dA/dw = 38 - 2w
38 - 2w = 0
38 = 2w
w = 38/2
w = 19
Answer:
2
Step-by-step explanation:
4.221 is greater because of the .221
.022 see
Answer:
CD = 14 cm; DE = 21 cm
Step-by-step explanation:
The perimeter is the sum of side lengths (in centimeters), so ...
CD + DE + CF + EF = 55
CD + DE + 8 + 12 = 55 . . . . . . . substittute for CF and EF
CD + DE = 35 . . . . . . . . . . . . . . subtract 20
___
The segment DF is a diagonal of the rhombus, so bisects angle D. That angle bisector divides ΔCDE into segments that are proportional. That is, ...
CD/DE = CF/EF = 8/12 = 2/3
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So, we have two segments whose sum is 35 (cm) and whose ratio is 2 : 3. The total of "ratio units is 2+3=5, so each must stand for a length unit of 35/5 = 7 (cm). The sides are ...
CD = 2·7 cm = 14 cm
DE = 3·7 cm = 21 cm
<em>Check</em>
CD + DE = (14 +21) cm = 35 cm . . . . . matches requirements
