Question 1201078
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With the ladder reaching 520 cm above the ground, we have a right triangle with hypotenuse and leg in the ratio 650:520 = 5:4, so the triangle is a scale model of a 3-4-5 right triangle.  The distance from the foot of the ladder to the base of the building is the other leg of the triangle, which is 3*130 = 390 cm.<br>
When the ladder is moved so that it reaches 520+80 = 600 cm up on the wall, the right triangle now has hypotenuse and leg in the ratio 650:600 = 13:12.  So now we have a scale model of a 5-12-13 right triangle; the distance from the foot of the ladder to the base of the building is now 5*50 = 250 cm.<br>
So the foot of the ladder is now 390-250 = 140 cm closer to the building.<br>
ANSWER: 140 cm closer<br>