Question

You tie a spherical balloon that is 2 feet in diameter to a stake in the ground.The string is 15 feet long.The wind blows and you observe that the top of the balloon is 8 feet over from the stake,as shown in the diagram.what is the height,b,of the balloon?

Answer 1

To solve this problem, we can use the Pythagorean theorem to find the height of the balloon. In particular, we can consider the right triangle formed by the stake, the top of the balloon, and the part of the string that is attached to the stake.

[asy]

unitsize(2 cm);

pair A, B, C, D, E;

A = (0,0);

B = (0,8);

C = extension(A,B,A+(1,0),B+(1,0));

D = extension(A,C,A+(0,1),C+(0,1));

E = extension(B,D,B+(0,-1),D+(0,-1));

draw(A--B--C--cycle);

draw(A--D--E--cycle);

draw(rightanglemark(A,D,C,2));

label("$A$", A, S);

label("$B$", B, N);

label("$C$", C, E);

label("$D$", D, E);

label("$E$", E, W);

[/asy]

Let $a$ be the distance from the stake to the top of the balloon, $b$ be the height of the balloon, and $c$ be the length of the string. We know that $a = 8$ feet and $c = 15$ feet, so we can use the Pythagorean theorem to find $b$:

$a^2 + b^2 = c^2$

$8^2 + b^2 = 15^2$

$64 + b^2 = 225$

$b^2 = 161$

$b = \sqrt{161} = \boxed{12.8}$ feet

Therefore, the height of the balloon is approximately 12.8 feet.