Friday

September 19, 2014

September 19, 2014

Posted by **Amie** on Monday, September 13, 2010 at 7:28pm.

2) A 10 foot tall lamppost causes a child 4 feet tall to cast a shadow of x feet on the ground. If the distance along the ground from the child to the lamppost is d meters, express x as a function.

- Math - function problems -
**Reiny**, Monday, September 13, 2010 at 7:38pmlet the side of the square base be x m

let the height be y m

I will assume the box has a lid so the surface area is made up of 2x^ + 4xy

then 2x^2 + 4xy = 12

4xy = 12-2x^2

y = (6-x^2)/(2x)

volume = x^2y

= x^2(6-x^2)/(2x)

= x(6-x^2)/2

for the second, you have similar triangles, so set up a ratio

4/x = 10/(x+d)

10x = 4x + 4d

take it from there

**Answer this Question**

**Related Questions**

calculus - Find the formula for the described function and state its domain. An ...

Calculus - An OPEN box has a square base and a volume of 108 cubic inches and ...

calc - a closed box has a base twice as long as it is wide.if its volume is 100 ...

PreCal - A square sheet of cardboard 18 inches is made into an open box (there ...

algebra - have 50 sq ft of material to make an open top box with a square base. ...

Algebra - A rectangular box with the volume 320 cu ft is built with a square ...

Pre Calculus - 1. A rectangular box has a square base, four sides, but no top. ...

calculus - A container company is tasked to make an open-top rectangular box ...

Math - you use a rectangular piece of cardboard 20 in by 30 to construct a box. ...

Math - Express as a function of two variables. An open box is to contain a ...