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MATH / In rectangle ABCD with AB=16, P is a point on BC so that ∠APD=90^(∘). TS is perpendicular to BC with BP=PT, as shown. PD intersects TS at Q. Point R is on CD such that RA passes th…

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problem

In rectangle ABCDABCD with AB=16,AB = 16, PP is a point on BCBC so that ∠APD=90∘\angle APD=90^{\circ}. TSTS is perpendicular to BCBC with BP=PTBP=PT, as shown. PDPD intersects TSTS at QQ. Point RR is on CDCD such that RARA passes through QQ. In △PQA\triangle PQA, PA=20PA=20, AQ=25AQ=25 and QP=15QP=15. [asy] size(7cm);defaultpen(fontsize(9)); real sd = 7/9 * 12; path extend(pair a, pair b) {return a--(10 * (b - a));} // Rectangle pair a = (0, 0); pair b = (0, 16); pair d = (24 + sd, 0); pair c = (d.x, b.y); draw(a--b--c--d--cycle); label("AA", a, SW);label("BB", b, NW);label("CC", c, NE);label("DD", d, SE); // Extra points and lines pair q = (24, 7); pair s = (q.x, 0); pair t = (q.x, b.y); pair r = IP(c--d, extend(a, q)); pair p = (12, b.y); draw(q--a--p--d--r--cycle);draw(t--s); label("RR", r, E); label("PP", p, N);label("QQ", q, 1.2 * NE + 0.2 * N);label("SS", s, S); label("TT", t, N); // Right angles and tick marks markscalefactor = 0.1; draw(rightanglemark(a, b, p)); draw(rightanglemark(p, t, s)); draw(rightanglemark(q, s, d));draw(rightanglemark(a, p, q)); add(pathticks(b--p, 2, spacing=3.4, s=10));add(pathticks(p--t, 2, spacing=3.5, s=10)); // Number labels label("1616", midpoint(a--b), W); label("2020", midpoint(a--p), NW); label("1515", midpoint(p--q), NE); label("2525", midpoint(a--q), 0.8 * S + E); [/asy] Find QR−RDQR - RD.
Plain-text mathematical notation (without MathML)
In rectangle ABCD with AB=16, P is a point on BC so that ∠APD=90^(∘). TS is perpendicular to BC with BP=PT, as shown.  PD intersects TS at Q.  Point R is on CD such that RA passes through Q.  In △PQA, PA=20, AQ=25 and QP=15. [asy]
size(7cm);defaultpen(fontsize(9));
real sd = 7/9 * 12;
path extend(pair a, pair b) {return a--(10 * (b - a));}

// Rectangle
pair a = (0, 0); pair b = (0, 16); pair d = (24 + sd, 0); pair c = (d.x, b.y);
draw(a--b--c--d--cycle);
label("A", a, SW);label("B", b, NW);label("C", c, NE);label("D", d, SE);

// Extra points and lines
pair q = (24, 7); pair s = (q.x, 0); pair t = (q.x, b.y);
pair r = IP(c--d, extend(a, q));
pair p = (12, b.y);
draw(q--a--p--d--r--cycle);draw(t--s);
label("R", r, E); label("P", p, N);label("Q", q, 1.2 * NE + 0.2 * N);label("S", s, S); label("T", t, N);

// Right angles and tick marks
markscalefactor = 0.1;
draw(rightanglemark(a, b, p)); draw(rightanglemark(p, t, s)); draw(rightanglemark(q, s, d));draw(rightanglemark(a, p, q));
add(pathticks(b--p, 2, spacing=3.4, s=10));add(pathticks(p--t, 2, spacing=3.5, s=10));

// Number labels
label("16", midpoint(a--b), W); label("20", midpoint(a--p), NW); label("15", midpoint(p--q), NE);
label("25", midpoint(a--q), 0.8 * S + E);
[/asy] Find QR−RD.
Original LaTeX notation
In rectangle $ABCD$ with $AB = 16,$ $P$ is a point on $BC$ so that $\angle APD=90^{\circ}$. $TS$ is perpendicular to $BC$ with $BP=PT$, as shown.  $PD$ intersects $TS$ at $Q$.  Point $R$ is on $CD$ such that $RA$ passes through $Q$.  In $\triangle PQA$, $PA=20$, $AQ=25$ and $QP=15$. [asy]
size(7cm);defaultpen(fontsize(9));
real sd = 7/9 * 12;
path extend(pair a, pair b) {return a--(10 * (b - a));}

// Rectangle
pair a = (0, 0); pair b = (0, 16); pair d = (24 + sd, 0); pair c = (d.x, b.y);
draw(a--b--c--d--cycle);
label("$A$", a, SW);label("$B$", b, NW);label("$C$", c, NE);label("$D$", d, SE);

// Extra points and lines
pair q = (24, 7); pair s = (q.x, 0); pair t = (q.x, b.y);
pair r = IP(c--d, extend(a, q));
pair p = (12, b.y);
draw(q--a--p--d--r--cycle);draw(t--s);
label("$R$", r, E); label("$P$", p, N);label("$Q$", q, 1.2 * NE + 0.2 * N);label("$S$", s, S); label("$T$", t, N);

// Right angles and tick marks
markscalefactor = 0.1;
draw(rightanglemark(a, b, p)); draw(rightanglemark(p, t, s)); draw(rightanglemark(q, s, d));draw(rightanglemark(a, p, q));
add(pathticks(b--p, 2, spacing=3.4, s=10));add(pathticks(p--t, 2, spacing=3.5, s=10));

// Number labels
label("$16$", midpoint(a--b), W); label("$20$", midpoint(a--p), NW); label("$15$", midpoint(p--q), NE);
label("$25$", midpoint(a--q), 0.8 * S + E);
[/asy] Find $QR - RD$.

level

Level 4

type

Geometry

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