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Kara is building a sandbox shaped like a kite for her nephew. The top two sides of the sandbox are 29 inches long. The bottom two sides are 25 inches long. The diagonal DB has a length of 40 inches. What is the length of the diagonal AC?

User Trufa
by
6.7k points

2 Answers

4 votes
The wording is unclear without a diagram. As such, there are two possible cases and two possible answers.

Case 1: Diagonal
\overline{DB} i
s formed by connecting the vertices formed by the meeting points of a 25-inch side and a 29-inch side.
Call the intersection point of
\overline{DB} and
\overline{AC} E.
\overline{AC} bisects
\overline{DB}, so
DE=BE=20\text{ inches}. Since the diagonals of a kite are perpendicular to each other,
\triangle AED and
\triangle CED are both right triangles. One has a hypotenuse of
29, and the other has a hypotenuse of
25, but both share a leg of
20. Using the Pythagorean Theorem, we can get that the length of the other leg in the triangle with a hypotenuse of
29 is
21. Similarly, for the triangle with a hypotenuse of
25, the other leg has a length of
15. Together, these legs make up
\overline{AC}, meaning
AC=21+15=36 \text{ inches}, our final answer.

Case 2: Diagonal
\overline{DB} i
s formed by connecting the vertices formed by the meeting points of the sides with equal lengths.
Call the intersection point of
\overline{DB} and
\overline{AC} E. We will focus on two triangles, namely
\triangle ADE and
\triangle ABE. Since diagonals intersect perpendicularly, these triangles are right triangles. One of them has a hypotenuse of
29, and the other has a hypotenuse of
25. They both share a leg that is half of
\overline{AC} because
\overline{DB} bisects
\overline{AC}. Let
AE=y and the non-shared leg of the right triangle with a hypotenuse of
29 equal
x. Since
DB=40, the non-shared leg of the other right triangle (the one with a hypotenuse of
25) has a length of
40-x. Using the Pythagorean Theorem, we can get the equations
x^2+y^2=29^2 and
(40-x)^2+y^2=25^2. These can simplify to
x^2+y^2=841 and
1600-80x+x^2 + y^2=625. Isolating the term
y^2, we can get
y^2=841-x^2 and
y^2=625-x^2+80x-1600. The latter can simplify to
y^2=-975-x^2+80x. Using substitution, we can combine the two equations into one and get
841-x^2=-975-x^2+80x. We can simplify that to
80x=1816, meaning
x=22.7. However, we are looking for
2y (
y is only half of
\overline{AC}). We can solve for
y using the Pythagorean Theorem and the triangle with a hypotenuse of
29 and a leg of
22.7. We get
y \approx 18.05, meaning
\overline{AC}=2y \approx 36.1 \text{ inches}, our final answer.
User Ellioh
by
7.0k points
4 votes

Answer:the length of the diagonal AC is 36. I just did the assignment! hope this helps

Explanation:

User Max Daroshchanka
by
6.5k points
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