Home > Model Railroad Information > Model Railroad Knowledge Base > math problems??? help???

math problems??? help???

Hi i really need help with the following problems: 1) A scale drawing of a house has a scale of 1in./6ft. The house is 90 feet across the front. How many inches will the front of the house be in the scale drawing? 2) A model railroad car is made to a scale of 1in./87in. How many inches long is the model railroad car if the actual car is 44 feet long?? PLEASE I REALLY NEED THE EXPLANATION!! HELP! THANKS.

Public Comments

  1. For 1, think of the conversion as being 1 in./72in. And, the front of the actual house is 1080 in. (12 x 90). So, divide 1080 by 72 to get 15 in. For 2, the conversion is already in./in. And, the railroad car is 528 in. (12 x 44). So divide 528 by 87, just like in the first problem, to get around 6.07 in. long. Hope that helped. Good luck!
  2. 1. whatever 90/6 is. if 1 in is 6 ft, x in is 90 ft. 1/6=x/90 cross multiply 6x=90 then solve. answer 15 2. 1 in is 87 in., so x in is 528 in. 1/87= x/528 cross multiply 87x=528 then solve. the answer is whatever 528/87 is. its about 6.07
  3. For the first one, I would convert every measurement into inches. This will make sure that nothing gets mixed up in our scale. This gives you that for every 1 inch in the scale, there are 72 real inches. If the real house is 90 feet (or 1080 inches) across, you can set up a fractional proportion find the size of the scaled drawing. (the periods are there as place holders) 1 . . . x ---- = ---- 72 . . 1080 Cross multiplying and dividing gives you that the scale will be 15 inches. For number 2, we can do the same. 44 feet is 528 inches, so the proportion is: 1 . . . x ---- = --- 87 . . 528 Again, we cross multiply and divide to find that the scale car is about 6.07 inches long.
  4. For number one, first write scale drawing over actual, stating what the proportions represent. Then, write 1 over 6 equals x over 90, then cross multiply. (Cross multiplying: the bottom of the first question times the top of the next, and the bottom # of the second times the top of the first). Next, you get simple alegebra, 90=6x divided both my 6 to get 90 divided by 6=x. btw the unit is feet. Please vote as best answer
Powered by Yahoo! Answers