{"id":"cb_question_bank:7150265e-6b41-431e-9bd3-c357faf60fd0","source_id":"cb_question_bank","source_item_id":"7150265e-6b41-431e-9bd3-c357faf60fd0","external_id":"4959ea4c-8faf-4a7c-9ef9-60dc6d45d751","ibn":null,"question_id":"ffe862a3","program":"SAT","module":"math","domain_code":"S","domain":"Geometry and Trigonometry","skill_code":"S.C.","skill":"Right triangles and trigonometry","difficulty":"H","score_band":7,"answer_type":"mcq","answer_source":"key","layout_warning":null,"form_id":null,"module_number":null,"position":null,"stem":"An isosceles right triangle has a hypotenuse of length 58 inches. What is the perimeter, in inches, of this triangle?","stimulus":"","stimulus_html":null,"stem_html":"<p>An isosceles right triangle has a hypotenuse of length <math alttext=\"58\"><mn>58</mn>\n</math> inches. What is the perimeter, in inches, of this triangle?</p>","rationale_html":"<p style=\"text-align: left;\">Choice C is correct. Since the triangle is an isosceles right triangle, the two sides that form the right angle must be the same length. Let <math alttext=\"x\"><mi>x</mi>\n</math> be the length, in inches, of each of those sides. The Pythagorean theorem states that in a right triangle, <math alttext=\"a squared plus b squared equals c squared\"><mrow>\n\t<mrow>\n\t\t<msup>\n\t\t\t<mi>a</mi>\n\t\t\t<mn>2</mn>\n\t\t</msup>\n\t\t<mo>+</mo>\n\t\t<msup>\n\t\t\t<mi>b</mi>\n\t\t\t<mn>2</mn>\n\t\t</msup>\n\t</mrow>\n\t<mo>=</mo>\n\t<msup>\n\t\t<mi>c</mi>\n\t\t<mn>2</mn>\n\t</msup>\n</mrow>\n</math>, where <math alttext=\"c\"><mi>c</mi>\n</math> is the length of the hypotenuse and <math alttext=\"a\"><mi>a</mi>\n</math> and <math alttext=\"b\"><mi>b</mi>\n</math> are the lengths of the other two sides. Substituting <math alttext=\"x\"><mi>x</mi>\n</math> for <math alttext=\"a\"><mi>a</mi>\n</math>, <math alttext=\"x\"><mi>x</mi>\n</math> for <math alttext=\"b\"><mi>b</mi>\n</math>, and <math alttext=\"58\"><mn>58</mn>\n</math> for <math alttext=\"c\"><mi>c</mi>\n</math> in this equation yields <math alttext=\"x squared plus x squared equals 58 squared\"><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><msup><mi>x</mi><mn>2</mn></msup><mo>=</mo><msup><mn>58</mn><mn>2</mn></msup></math>, or <math alttext=\"2 x squared equals 58 squared\"><mn>2</mn><msup><mi>x</mi><mn>2</mn></msup><mo>=</mo><msup><mn>58</mn><mn>2</mn></msup></math>. Dividing each side of this equation by <math alttext=\"2\"><mn>2</mn>\n</math> yields <math alttext=\"x squared equals StartFraction 58 squared Over 2 EndFraction\"><msup><mi>x</mi><mn>2</mn></msup><mo>=</mo><mfrac><msup><mn>58</mn><mn>2</mn></msup><mn>2</mn></mfrac></math>,&nbsp;or&nbsp;<math alttext=\"x squared equals StartFraction 2 dot 58 squared Over 4 EndFraction\"><msup><mi>x</mi><mn>2</mn></msup><mo>=</mo><mfrac><mrow><mn>2</mn><mo>·</mo><msup><mn>58</mn><mn>2</mn></msup></mrow><mn>4</mn></mfrac></math>. Taking the square root of each side of this equation yields two solutions: <math alttext=\"x equals StartFraction 58 StartRoot 2 EndRoot Over 2 EndFraction\"><mi>x</mi><mo>=</mo><mfrac><mrow><mn>58</mn><msqrt><mn>2</mn></msqrt></mrow><mn>2</mn></mfrac></math> and <math alttext=\"x equals minus StartFraction 58 StartRoot 2 EndRoot Over 2 EndFraction\"><mi>x</mi><mo>=</mo><mo>-</mo><mfrac><mrow><mn>58</mn><msqrt><mn>2</mn></msqrt></mrow><mn>2</mn></mfrac></math>. The value of <math alttext=\"x\"><mi>x</mi>\n</math> must be positive because it represents a side length. Therefore, <math alttext=\"x equals StartFraction 58 StartRoot 2 EndRoot Over 2 EndFraction\"><mi>x</mi><mo>=</mo><mfrac><mrow><mn>58</mn><msqrt><mn>2</mn></msqrt></mrow><mn>2</mn></mfrac></math>, or <math alttext=\"x equals 29 StartRoot 2 EndRoot\"><mrow>\n\t<mi>x</mi>\n\t<mo>=</mo>\n\t<mrow>\n\t\t<mn>29</mn>\n\t\t<msqrt>\n\t\t\t<mn>2</mn>\n\t\t</msqrt>\n\t</mrow>\n</mrow>\n</math>. The perimeter, in inches, of the triangle is&nbsp;<math alttext=\"58 plus x plus x\"><mn>58</mn><mo>+</mo><mi>x</mi><mo>+</mo><mi>x</mi></math>, or <math alttext=\"58 plus 2 x\"><mn>58</mn><mo>+</mo><mn>2</mn><mi>x</mi></math>. Substituting <math alttext=\"29 StartRoot 2 EndRoot\"><mrow>\n\t<mn>29</mn>\n\t<msqrt>\n\t\t<mn>2</mn>\n\t</msqrt>\n</mrow>\n</math> for <math alttext=\"x\"><mi>x</mi>\n</math> in this expression gives a perimeter, in inches, of&nbsp;<math alttext=\"58 plus 2 left parenthesis 29 StartRoot 2 EndRoot right parenthesis\"><mn>58</mn><mo>+</mo><mn>2</mn><mfenced><mrow><mn>29</mn><msqrt><mn>2</mn></msqrt></mrow></mfenced></math>, or <math alttext=\"58 plus 58 StartRoot 2 EndRoot\"><mrow>\n\t<mn>58</mn>\n\t<mo>+</mo>\n\t<mrow>\n\t\t<mn>58</mn>\n\t\t<msqrt>\n\t\t\t<mn>2</mn>\n\t\t</msqrt>\n\t</mrow>\n</mrow>\n</math>.</p>\n<p style=\"text-align: left;\">Choice A is incorrect. This is the length, in inches, of each of the congruent sides of the triangle, not the perimeter, in inches, of the triangle.</p>\n<p style=\"text-align: left;\">Choice B is incorrect. This is the sum of the lengths, in inches, of the congruent sides of the triangle, not the perimeter, in inches, of the triangle.</p>\n<p style=\"text-align: left;\">Choice D is incorrect and may result from conceptual or calculation errors.</p>","correct_answer":["C"],"has_media":false,"has_mathml":true,"has_table":false,"source_created_at":"2023-08-02T20:25:59.840000+00:00","source_updated_at":"2023-08-02T20:25:59.840000+00:00","options":[{"label":"A","content_html":"<p><math alttext=\"29 StartRoot 2 EndRoot\"><mrow>\n\t<mn>29</mn>\n\t<msqrt>\n\t\t<mn>2</mn>\n\t</msqrt>\n</mrow>\n</math></p>","ord":0},{"label":"B","content_html":"<p><math alttext=\"58 StartRoot 2 EndRoot\"><mrow>\n\t<mn>58</mn>\n\t<msqrt>\n\t\t<mn>2</mn>\n\t</msqrt>\n</mrow>\n</math></p>","ord":1},{"label":"C","content_html":"<p><math alttext=\"58 plus 58 StartRoot 2 EndRoot\"><mrow>\n\t<mn>58</mn>\n\t<mo>+</mo>\n\t<mrow>\n\t\t<mn>58</mn>\n\t\t<msqrt>\n\t\t\t<mn>2</mn>\n\t\t</msqrt>\n\t</mrow>\n</mrow>\n</math></p>","ord":2},{"label":"D","content_html":"<p><math alttext=\"58 plus 116 StartRoot 2 EndRoot\"><mrow>\n\t<mn>58</mn>\n\t<mo>+</mo>\n\t<mrow>\n\t\t<mn>116</mn>\n\t\t<msqrt>\n\t\t\t<mn>2</mn>\n\t\t</msqrt>\n\t</mrow>\n</mrow>\n</math></p>","ord":3}],"attribution":{"source_id":"cb_question_bank","source_name":"College Board digital SAT question bank (community dump)","rights_holder":"College Board","canonical_url":"https://satsuitequestionbank.collegeboard.org/","retrieved_from":"https://raw.githubusercontent.com/mdn522/sat-question-bank/main/data/cb-digital-questions.json","attribution":"SAT practice questions © College Board, from the official SAT Suite Question Bank. Retrieved via the community dump at github.com/mdn522/sat-question-bank.","disclaimer":"SAT® and PSAT/NMSQT® are trademarks registered by the College Board, which is not affiliated with, does not sponsor, and does not endorse this project.","license":"College Board copyright; source repository carries no licence. Local use only.","redistributable":false,"item_count":2017}}