BrainDen.com - Brain Teasers # Donald Cartmill

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1. Machine A worked 40 hours. 45x = 40(x + 5 ); 45x = 40x +200.; 5x = 200 ;x = 40
2. Comfortable
3. The area would be that of the original triangle,however that area would vary as determined by the length of the 3rd side
4. operates on the 1st ; Turns the gloves inside out for # 2; operates bare handed on the 3rd
5. If the question is : What is the ratio of the arc length to the perpendicular length from the center of one side of the square to the arc ??? Then assuming diameter of 1" ; the diagonal of the largest square would also be 1 ; this divides the square into 2 isosceles triangles ,whose angles are 45,45,90 In a 45 degree triangle the sides are = Hsin angle or 1 sin 45 = 0.707; therefore i/2 of the lt of a side is 0.353 . The radius is 0.5. 0.5 - 0.353 = the rise 0.147 the distance from arc to square Now the circumference is pie D or 3.14 D, 3.14 (1) = 3.14; acr length 3.14 divided by 4 =0.7853 ratio of arc length to rise ....0.7853/0.147 = 5.342 :1 Previously I assumed the wrong question ,However assuming a diameter of 1" R = 0.5" . I calculated the rise ( r ),which is the distance from the one side of the square at the mid point of that side to the arc or circumference . That value r =0.147 therefore the ratio of r/R = 0.147/0.5 0.147 /0.5 = 1/X; 0.147X = 1x 0.5; X = 1 /0.147; Ratio r / R is 1 /6.802 Quote
6. total of \$ 0.75 ; Arrange 4 pennies in a circle around a penny in the center (A ) such that none of the outside pennies are on the same diameter passing thru (A) Let's assume that as we look at our screen (B) is directly below (A) at a distance of the radius ; Moving CW up to the left more than 90 deg is (C) ; continuing CW approx 70 degrees which stops us short of being diametrically opposite (B) is location of (D) : continue CW about 90 degrees for (E). You have 4 triangles which do NOT over lap ABC; ACD ; ADE ; AEB . You then have 6 triangles created by lines from(B) to (D) and from (C) to (E) These triangles being BCD ; BDE; BDA; CDE ; CEA ; CEB. So we have 4 @ 0.10 = \$040 and 6 @ .05 = 0.30 for a total of \$ 0.70 plus the 5 pennies = 75 cents
7. Total of \$ 0.70 ; Arrange 4 pennies in a circle around a penny in the center (A ) such that none of the outside pennies are on the same diameter passing thru (A) Let's assume that as we look at our screen (B) is directly below (A) at a distance of the radius ; Moving CW up to the left more than 90 deg is (C) ; continuing CW approx 70 degrees which stops us short of being diametrically opposite (B) is location of (D) : continue CW about 90 degrees for (E). You have 4 triangles which do NOT over lap ABC; ACD ; ADE ; AEB . You then have 6 triangles created by lines from(B) to (D) and from (C) to (E) These triangles being BCD ; BDE; BDA; CDE ; CEA ; CEB. So we have 4 @ 0.10 = \$040 and 6 @ .05 = 0.30 for a total of \$ 0.70
8. If the question is : What is the ratio of the arc length to the perpendicular length from the center of one side of the square to the arc ??? Then assuming diameter of 1" ; the diagonal of the largest square would also be 1 ; this divides the square into 2 isosceles triangles ,whose angles are 45,45,90 In a 45 degree triangle the sides are = Hsin angle or 1 sin 45 = 0.707; therefore i/2 of the lt of a side is 0.353 . The radius is 0.5. 0.5 - 0.353 = the rise 0.147 the distance from arc to square Now the circumference is pie D or 3.14 D, 3.14 (1) = 3.14; acr length 3.14 divided by 4 =0.7853 ratio of arc length to rise ....0.7853/0.147 = 5.342 :1
9. Suppose i have a circle. I cut off its arcs such that it became the biggest possible square i could make from that circle. This is clear Several clarifications are required: What's the ratio of the edge of the circle .....(1) edge of the circle a) the circumference or b) one of the arcs clarification required: to the middle of the edge of the square ? (assume minimum length) to the radius of the circle. . Is the question : What is the ratio of the arc length to the perpendicular length from the center of one side of the square to the arc ??? Suppose i have a circle. I cut off its arcs such that it became the biggest possible square i could make from that circle. What's the ratio of the edge of the circle to the middle of the edge of the square (assume minimum length) to the radius of the circle.