document.write( "Question 1040515: The diagonal of a rectangle is 10 inches and the area is 45 square inches. Find the dimensions of the triangle, correct to one decimal place. \n" ); document.write( "
Algebra.Com's Answer #655335 by rothauserc(4718)![]() ![]() You can put this solution on YOUR website! let l be length and w be width of the rectangle, then \n" ); document.write( ": \n" ); document.write( "1) l^2 + w^2 = 10^2 \n" ); document.write( "2) l * w = 45 \n" ); document.write( ": \n" ); document.write( "we have two equations in two unknowns \n" ); document.write( ": \n" ); document.write( "solve 2 for l and substitute in 1 \n" ); document.write( "l = 45/w \n" ); document.write( "(45/w)^2 + w^2 = 100 \n" ); document.write( ": \n" ); document.write( "(2025/w^2) + w^2 = 100 \n" ); document.write( ": \n" ); document.write( "multiply both sides of = by w^2 \n" ); document.write( ": \n" ); document.write( "2025 + w^4 = 100w^2 \n" ); document.write( ": \n" ); document.write( "w^4 -100w^2 + 2045 = 0 \n" ); document.write( ": \n" ); document.write( "let u = w^2 \n" ); document.write( ": \n" ); document.write( "u^2 -100u + 2025 = 0 \n" ); document.write( ": \n" ); document.write( "use quadratic equation \n" ); document.write( ": \n" ); document.write( "u = (100 + square root( (-100)^2 - 4(1)(2025) ) ) / 2 = 71.8 \n" ); document.write( "u = (100 - square root( (-100)^2 - 4(1)(2025) ) ) / 2 = 28.2 \n" ); document.write( ": \n" ); document.write( "since u = w^2, we have \n" ); document.write( ": \n" ); document.write( "w^2 = 71.8 and w = 8.5 \n" ); document.write( "w^2 = 28.2 and w = 5.3 \n" ); document.write( ": \n" ); document.write( "we have 2 solutions for l as well \n" ); document.write( ": \n" ); document.write( "l = 45/8.5 = 5.3 \n" ); document.write( "l = 45/5.3 = 8.5 \n" ); document.write( ": \n" ); document.write( "Our 2 solutions are \n" ); document.write( "********************** \n" ); document.write( "w = 8.5 and l = 5.3 \n" ); document.write( "w = 5.3 and l = 8.5 \n" ); document.write( "********************* \n" ); document.write( ": \n" ); document.write( "note that \n" ); document.write( "8.5 * 5.3 = 45.05 \n" ); document.write( "8.5^2 + 5.3^2 = 100.34 and square root of 100.34 = 10.02 \n" ); document.write( ": \n" ); document.write( " |