Answer: the 3rd one or the 1rst one
Step-by-step explanation:
Consider the parallelogram shown below.
The lengths of the sides are a and b.
The lengths of the diagonals are 2x and 2y.
Because the diagonals are both congruent and perpendicular, therefore there are two right triangles as shown.
Note that x = y.
Because x = y, each right triangle is isosceles and has the angles 90°, 45° and 45°.
From the Pythagorean theorem,
For one right triangle,
a² = x² + y² = x² + x² = 2x².
For the other right triangle,
b² = y² + x² = x² + x² = 2x²
Therefore
a² = b²
a = b
It follows that all sides of the parallelogram are equal and each angle is
45+45 = 90°
Therefore the parallelogram is a square.
Answer:
X^4 over 4
Step-by-step explanation:
Answer:
Step-by-step explanation:
Distance upstream = (34-c)(39/60) miles
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Distance downstream = (34+c)(29/60) miles
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Equation:
distance = rate*time
distance up = distance down
(34-c)(39/60) = (34+c)(29/60)
Multiply both sides by 60 to get:
39(34-c) = 29(34+c)
39*34 - 39c = 29*34 + 29c
68c = 340
c = 5 mph speed of the current