Two vertical poles 20 m and 30 m high, are 60 m apart. A rope is to be attached from the top of one pole to a point on the ground halfway between the poles, and then to the top of the other pole. How long a rope is needed?

depends on how many days you are talking about

step-by-step explanation:

answer: a

step-by-step explanation: the answer is a due to the rule of symmetry; that a line of symmetry must divide a figure into 2 pieces that are the exact same, only reflected over a line of symmetry. b and c do not have lines of symmetry and would not divide the figure evenly, thus making the answer a.

the cross section of an object is the shape you get when you cut straight through an object.

thus the cross section of the human hair is a circle. hence the cross sectional area is the area of a circle and area of circle is :

a = 3.14 × r²

we are given that the average width of human hair is = 4 × (1 / 10³) cm.

so the diameter of the circle is = 4 × (1 / 10³) cm.

∴ radius r = (diameter/2) = 2 × (1/10³) cm

now area a = 3.14 × (2 × (1/10³))² cm²

scientific notation is a standard way of writing very large and very small numbers so that they’re easier to both compare and use in computations. to write in scientific notation, follow the form

n × 10 ᵃ

where n is a number between 1 and 10, but not 10 itself, and a is an integer (positive or negative number).

so area can be rewritten in scientific notation as :

⇒ 3.14 × 4 × (1/10⁶)

⇒ 12.56 × 10 ⁻⁶ cm²

⇒1.256 × 10⁻⁷ cm²