CDE~PQR CD = 9 m EC = 15 what is the length of RP

1 answer

Since CD = 9 m and EC = 15 m, we can find the length of DE.

DE = EC - CD
DE = 15 m - 9 m
DE = 6 m

Now, we have a right triangle RPQ where PQ is the hypotenuse, PR is the base, and QR is the height.

Using the Pythagorean theorem, we can find the length of PQ.

PQ^2 = PR^2 + QR^2

Since CDE~PQR, we can set up the following proportions:

PQ/DE = PR/CD

PQ/6 = PR/9

Cross-multiplying, we get:

PQ * 9 = 6 * PR

9PQ = 6PR

Dividing both sides by 6, we get:

(9/6)PQ = PR

PQ = (3/2)PR

Substituting this back into the Pythagorean theorem equation, we have:

(3/2)PR^2 = PR^2 + QR^2

Multiplying through by 2, we get:

3PR^2 = 2PR^2 + 2QR^2

Subtracting 2PR^2 from both sides, we get:

PR^2 = 2QR^2

Dividing through by QR^2, we get:

(PR/QR)^2 = 2

Taking the square root of both sides, we get:

PR/QR = sqrt(2)

Since PR/QR = PQ/QR, we can substitute back in the value we found earlier for PQ/QR:

sqrt(2) = (3/2)PR/QR

Since CD = 9 m, and PR/QR = sqrt(2), we can set up the following proportion:

CD/QR = PR/QR

9/QR = sqrt(2)

Cross-multiplying, we get:

9 = QR * sqrt(2)

Dividing both sides by sqrt(2), we get:

QR = 9/sqrt(2)

Multiplying the numerator and denominator of the right-hand side by sqrt(2), we can rationalize the denominator:

QR = (9/sqrt(2)) * (sqrt(2)/sqrt(2))
QR = 9 * sqrt(2) / 2
QR = (9/2) * sqrt(2)

Therefore, the length of QR is (9/2) * sqrt(2) m.