A cross section is the two dimensional shape that is created when a slice is made through a solid figure by an intersection of a plane and the solid body.
A square pyramid is a pyramid with a square base.
Case 1: When the plane intersects the square pyramid at an angle perpendicular to the base but not through the vertex. In this case a trapezoid is formed.
Case 2: When the plane intersects the square pyramid at an angle perpendicular to the base and through the vertex. In this case a triangle is formed.
Case 3: When the plane intersects the square pyramid at an angle parallel to the base. In this case a square is formed.
<span>Therefore, a
cross section made by the intersection of a plane and a square
pyramid at an angle either parallel or perpendicular to the base can be of shapes:
-square
-triangle
-trapezoid</span>
Let 'x' be the distance from THE far bank where 700 is the distance to the NEAR bank
boat one has travelled 700 (rate = 700/unit time) boat two has travelled x rate = x / unit time
boat one then travels x + 400 more and boat two travels 700 + (700+x -400) more when they meet
The time is the same rate x time = distance distance/rate = time equate the distances divided by the respective rates
(700 + x + 400)/700 = ( x + 700 + (700+x-400) )/x
1100x + x^2 = 1400x + 700000
x^2-300x -700000 = 0 quadratic formula yields x = 1000
One boat travels 700 the other 1000 whe they first meet.....width of river = 700+ 1000 = 1700 m
The first answer is going to be 15.42 (so b) and the second is going to be 10.67 (so a)
