Help me with this please !!!!!!!!!!!!!
1 answer:
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Answer:
2 hours
Step-by-step explanation:
Let x mph be the speed of motorboat in still water and y mph be the speed of current.
A raft and a motorboat simultaneously leave from the same point and move down the river, then speeds down the river are:
motorboat = x + y mph
raft = y mph
In two hours they will cover:
motorboat = 2(x+y) miles
raft = 2y miles
After 2 hours the motorboat turns around and starts moving towards the raft (against the current), so its speed is now x - y mph.
Let t be the time they move towards each other. In t hours, they cover
motorboat = t(x - y) miles
raft = ty miles
The distance from the starting point to the turning point is the same as the sum of the distances the raft covers and the motorboat covers after turning around, so
Answer:
The true statements are:
m∠ 3 + m∠ 4 = 180° ⇒ 1st
m∠ 2 + m∠ 4 + m∠ 6 = 180° ⇒ 2nd
m∠ 2 + m∠ 4 = m∠ 5 ⇒ 3rd
Step-by-step explanation:
* Look to the attached diagram to answer the question
# m∠ 3 + m∠ 4 = 180°
∵ ∠ 3 and ∠ 4 formed a straight angle
∵ The measure of the straight angle is 180°
∴ m∠ 3 + m∠ 4 = 180° ⇒ <em>true</em>
# m∠ 2 + m∠ 4 + m∠ 6 = 180°
∵ ∠ 2 , ∠ 4 , ∠ 6 are the interior angles of the triangle
∵ The sum of the measures of interior angles of any Δ is 180°
∴ m∠ 2 + m∠ 4 + m∠ 6 = 180° ⇒ <em>true</em>
# m∠ 2 + m∠ 4 = m∠ 5
∵ In any Δ, the measure of the exterior angle at one vertex of the
triangle equals the sum of the measures of the opposite interior
angles of this vertex
∵ ∠ 5 is the exterior angle of the vertex of ∠ 6
∵ ∠2 and ∠ 4 are the opposite interior angles to ∠ 6
∴ m∠ 2 + m∠ 4 = m∠ 5 ⇒ <em>true </em>
# m∠1 + m∠2 = 90°
∵ ∠ 1 and ∠ 2 formed a straight angle
∵ The measure of the straight angle is 180°
∴ m∠1 + m∠2 = 90° ⇒ <em>Not true</em>
# m∠4 + m∠6 = m∠2
∵ ∠ 4 , ∠ 6 , ∠ 2 are the interior angles of a triangle
∵ There is no given about their measures
∴ We can not says that the sum of the measures of ∠ 4 and ∠ 6 is
equal to the measure of ∠ 2
∴ m∠4 + m∠6 = m∠2 ⇒ <em>Not true</em>
<em></em>
# m∠2 + m∠6 = m∠5
∵ ∠ 5 is the exterior angle at the vertex of ∠ 6
∴ m∠ 2 + m∠ 6 = m∠ 5 ⇒ <em>Not true</em>
