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Answer:</h2><h2>51.</h2>
Hope this will help you lot.
Lets day the original price of the dvd player was $100,
36% marked down means you pay $64x
64x = $41.60
100x = 100/54 x 41.60 = 4160/64 = #65.00 = original cost
similarly, stereo tuners = 100/78 x 69.42 = 6942/78 = $89 original cost
DVD = 65- 41.60 = $ 23. 40 less
Stereo = 89- 69.42 = $ 19.58 less
Diffrence is $ 3.82
so your answer is the dvd player price was reduced by $3.82 more than the stereo tuner.
Figure out the radius then divide it by two. The diameter is one end of a circle to another.
Use the formula a^2+b^2=c^ which is 7.21