MathDB

Problems(2)

Circle Tangent to Triangle

Source: 2021 Fall AMC 10A #15

11/11/2021
Isosceles triangle ABCABC has AB=AC=36AB = AC = 3\sqrt6, and a circle with radius 525\sqrt2 is tangent to line ABAB at BB and to line ACAC at CC. What is the area of the circle that passes through vertices AA, BB, and C?C? <spanclass=latexbold>(A)</span>24π<spanclass=latexbold>(B)</span>25π<spanclass=latexbold>(C)</span>26π<spanclass=latexbold>(D)</span>27π<spanclass=latexbold>(E)</span>28π<span class='latex-bold'>(A) </span>24\pi\qquad<span class='latex-bold'>(B) </span>25\pi\qquad<span class='latex-bold'>(C) </span>26\pi\qquad<span class='latex-bold'>(D) </span>27\pi\qquad<span class='latex-bold'>(E) </span>28\pi
AMC 10AMCAMC 10 A
Pythagorean or Similar Triag

Source: 2021 AMC 10B #15

11/17/2021
In square ABCDABCD, points PP and QQ lie on AD\overline{AD} and AB\overline{AB}, respectively. Segments BP\overline{BP} and CQ\overline{CQ} intersect at right angles at RR, with BR=6BR=6 and PR=7PR=7. What is the area of the square?
[asy] size(170); defaultpen(linewidth(0.6)); real r = 3.5; pair A = origin, B = (5,0), C = (5,5), D = (0,5), P = (0,r), Q = (5-r,0), R = intersectionpoint(B--P,C--Q); draw(A--B--C--D--A^^B--P^^C--Q^^rightanglemark(P,R,C,7)); dot("AA",A,S); dot("BB",B,S); dot("CC",C,N); dot("DD",D,N); dot("QQ",Q,S); dot("PP",P,W); dot("RR",R,1.3*S); label("77",(P+R)/2,NE); label("66",(R+B)/2,NE); [/asy] <spanclass=latexbold>(A)</span>85<spanclass=latexbold>(B)</span>93<spanclass=latexbold>(C)</span>100<spanclass=latexbold>(D)</span>117<spanclass=latexbold>(E)</span>125<span class='latex-bold'>(A) </span>85\qquad<span class='latex-bold'>(B) </span>93\qquad<span class='latex-bold'>(C) </span>100\qquad<span class='latex-bold'>(D) </span>117\qquad<span class='latex-bold'>(E) </span>125
AMCAMC 10AMC 10 B