No.d
37,619
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Answer:
18
Step-by-step explanation:
This question boils down to this:
"What is the diagonal of a square with a side length of 90 ft?"
The key to this question is the properties of squares.
All of the angles in a square are right, (90°) but that diagonal is going to bisect two of those into 45° angles.
Now we have two triangles, each with angle measures of 45°, 45°. and 90°.
(an isoceles right triangle)
This 45-45-90 tirnalge is one of two special triangles (the other being the 30-60-90) and here is its special property: the sides opposite these angles can be put as x, x, and x√2 respectively. Why? Well, we know that our triangle is isoceles (the congruent base angles ⇔ congruent sides) and so we call those x...by the Pythagorean theorem...a² + b² = c²...2x² = c²...x√2 = c!
In our case here, that diagonal, being the hypotenuse of our triangle, is going to be 90√2 feet, or approximately 127.3 feet.
Let, the speed of boat = x
Speed of current = y
So, x + y = 280/7
x + y = 40 ---- first equation
x - y = 280/14
x - y = 20
x = 20 + y
Substitute this value of x in first equation,
20 + y + y = 40
2y = 40 - 20
y = 20/2
y = 10
Substitute this in first equation,
x + 10 = 40
x = 30
In short, Speed of Boat = 30 mph, & speed of current = 10 mph
Hope this helps!
<h3>
Answer: D) 144 square cm</h3>
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Explanation:
A square has all four sides that are the same length. So all four sides are 12 cm
area = side*side = 12*12 = 144 cm^2
Or you could say
area = (side)^2 = (12)^2 = 144 cm^2
Squaring a number is the same as multiplying it by itself. Hence the name "square" refers to a side length pairing up with its corresponding area value.
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Side note: The perimeter is 4*(side) = 4*12 = 48 cm. It's possible that choice B is put in there as a trick answer.
